Method and system for collecting leukoreduced red blood cells

ABSTRACT

A method and system for collecting leukoreduced red blood cells employing a spinning membrane separator including a housing having an upper end region and a lower end region in an operating position with a red blood cell outlet in the upper end region of the housing and a whole blood inlet in the lower end region of the housing. The method and system provide for flowing additive solution into the whole blood inlet of the housing to prime the separator; flowing whole blood into the whole blood inlet of the housing; separating red blood cells from the whole blood; flowing separated red blood cells out of the red blood cell outlet of the housing; combining the separated red blood cells with additive solution; passing the separated red blood cells and additive solution combination through a leukoreduction filter; and collecting the filtered red blood cells and additive solution.

FIELD OF THE DISCLOSURE

The present application is related, in part, to separation devices ofthe type employing relatively rotating surfaces, at least one of whichcarries a membrane for filtering a component from fluid passed betweenthe surfaces; to fluid flow circuits and systems incorporating such aseparator; and to the use of such systems to separate biological cells,such as red cells, plasma or white cells, from whole blood, a storagemedium, a suspension medium, a supernatant, or the like.

BACKGROUND

Traditional blood collection continues to rely heavily on manualcollection of whole blood from healthy donors through blood drives, fromdonor visits to blood centers or hospitals and the like. In typicalmanual collection, whole blood is collected by simply flowing it, underthe force of gravity and venous pressure, from the vein of the donorinto a collection container. The amount of whole blood drawn istypically a “unit,” which is about 450 ml.

More specifically, such a collection typically employs a pre-assembledarrangement of tubing and containers or bags, including a flexibleplastic primary container or bag for receiving a unit of whole bloodfrom a donor and one or more “satellite” containers or bags. The bloodis first collected in the primary container, which also contains ananticoagulant (typically containing sodium citrate, phosphate anddextrose—often referred to as CPD). A preservative (often called an“additive solution” or AS, and commonly containing a saline, adenine andglucose medium—which is referred to as SAG) may be included as part of alarger assembly of bags and tubes that are used in processing after theblood is collected.

After collection of a unit of whole blood, it is common practice inblood banking to transport the unit of whole blood, with connectedtubing and containers, to a blood component processing laboratory,commonly referred to as a “back lab,” for further processing. Furtherprocessing usually entails manually loading the primary container andassociated tubing and satellite containers into a centrifuge to separatethe whole blood into components such as concentrated red cells andplatelet-rich or platelet-poor plasma. These components are thenmanually expressed from the primary container into other pre-connectedsatellite containers, and may be again centrifuged to separate theplatelets from plasma. Subsequently, the blood components may beleukoreduced by filtration for further processing or storage. In short,this process is time consuming, labor intensive, and subject to possiblehuman error.

Another routine task performed by blood banks and transfusion center is“cell washing.” This may be performed to remove and/or replace theliquid medium (or a part thereof) in which the cells are suspended, toconcentrate or further concentrate cells in a liquid medium, and/or topurify a cell suspension by the removal of unwanted cellular or othermaterial.

Previous cell washing systems most typically involved centrifugation ofa cell-suspension, decanting of the supernatant, re-suspension ofconcentrated cells in new media, and possible repetition of these stepsuntil the cells of the suspension are provided at an adequately high orotherwise desirable concentration. Centrifugal separators used in theprocessing of blood and blood components have commonly been used in suchcell-washing methods.

These processes are also quite time consuming, requiring repeated manualmanipulation of the blood or blood components and assembly ordisassembly of various fluid processing apparatus. This, of course,increases not only the costs, but the potential for human error ormistake. Accordingly, despite decades of advancement in blood separationdevices and processes, there continues to be a desire for better and/ormore efficient separation devices, systems and methods applicable tobasic blood collection and processing modalities.

While many of the prior blood separation apparatus and procedures haveemployed centrifugal separation principles, there is another class ofdevices, based on the use of a membrane, that has been used forplasmapheresis, that is separating plasma from whole blood. Morespecifically, this type of device employs relatively rotating surfaces,at least one or which carries a porous membrane. Typically the deviceemploys an outer stationary housing and an internal spinning rotorcovered by a porous membrane.

One such well-known plasmapheresis device is the Autopheresis-C®separator sold by Fenwal, Inc. of Lake Zurich, Ill. A detaileddescription of a spinning membrane separator may be found in U.S. Pat.No. 5,194,145 to Schoendorfer, which is incorporated by referenceherein. This patent describes a membrane-covered spinner having aninterior collection system disposed within a stationary shell. Blood isfed into an annular space or gap between the spinner and the shell. Theblood moves along the longitudinal axis of the shell toward an exitregion, with plasma passing through the membrane and out of the shellinto a collection bag. The remaining blood components, primarily redblood cells, platelets and white cells, move to the exit region betweenthe spinner and the shell and then are typically returned to the donor.

Spinning membrane separators have been found to provide excellent plasmafiltration rates, due primarily to the unique flow patterns (“Taylorvortices”) induced in the gap between the spinning membrane and theshell. The Taylor vortices help to keep the blood cells from depositingon and fouling or clogging the membrane.

While spinning membrane separators have been widely used for thecollection of plasma, they have not typically been used for thecollection of other blood components, specifically red blood cells.Spinning membrane separators also have not typically been used for cellwashing. One example of a spinning membrane separator used in thewashing of cells such as red blood cells is described in U.S. Pat. No.5,053,121 which is also incorporated by reference in its entirety.However, the system described therein utilizes two separate spinnersassociated in series or in parallel to wash “shed” blood of a patient.Other descriptions of the use of spinning membrane separators forseparation of blood or blood components may also be found in U.S. Pat.Nos. 5,376,263; 4,776,964; 4,753,729; 5,135,667 and 4,755,300.

The subject matter disclosed herein provides further advances inmembrane separators, potential cost reduction and various other advancesand advantages over the prior manual collection and processing of blood.

SUMMARY OF THE DISCLOSURE

The present subject matter has a number of aspects which may be used invarious combinations, and the disclosure of one or more specificembodiments is for the purpose of disclosure and description, and notlimitation. This summary highlights only a few of the aspects of thissubject matter, and additional aspects are disclosed in the drawings andthe more detailed description that follows.

In accordance with one aspect of the disclosure, an automated wholeblood separation system is provided that comprises a disposable fluidflow circuit module and a durable controller module that is configuredto cooperate with and control fluid flow through the fluid circuit. Thedisposable fluid circuit includes a whole blood fluid flow path with awhole blood inlet for connection to a unit of whole blood, such as theprimary container of whole blood previously collected from a donor, anda cell preservation solution flow path with an inlet for connection to asource of cell preservation solution, such as Adsol® solution, availablefrom Fenwal, Inc. of Lake Zurich Ill., USA.

The disposable fluid circuit also includes a separator with an outerhousing, such as a generally cylindrical outer housing, and an innerrotor mounted within the housing for rotation relative to the housing. Agap is defined between an outer surface of the rotor and an innersurface of the housing and at least one of the surfaces comprises afilter membrane configured to allow the passage of plasma through themembrane while substantially blocking red blood cells. The outer housinghas an inlet that is in fluid communication with the whole blood and/orcell preservation solution flow paths and is also in flow communicationwith the gap between the housing and the rotor, for directing wholeblood and/or cell preservation solution into the gap. The housingincludes a first outlet communicating with the gap for withdrawing ablood component such as concentrated red cells and the housing and/orrotor includes a second outlet communicating with the side of themembrane facing away from the gap for collecting a blood component thatpasses through the membrane, such as plasma. The housing is configuredto have a top and a bottom, with the inlet located proximate to thebottom of the housing and the first and second outlets located proximateto the top of the housing. The first housing outlet communicating withthe gap is in flow communication with an outlet fluid flow path forconnection to a storage container, such as a red cell storage containerand, optionally, a leukocyte reduction filter.

The durable controller of the system may include a programmable controlsystem for controlling processing of whole blood through the fluidcircuit and, if desired, for controlling the rotational speed of theseparator rotor, and/or any associated pumps and/or clamps forcontrolling flow rates of fluid through the fluid circuit.

For example, the durable controller may include an inlet pump configuredto control fluid flow through the whole blood and/or cell preservativesolution flow paths and an outlet pump configured to control fluid flowthrough the housing outlet that communicates with the gap. As notedabove, these may be controlled by a programmable control system of thedurable controller. The controller may also include a hematocritdetector that cooperates with the whole blood flow path for measuringhematocrit of the blood flowing through the whole blood path and othervalves, pumps and sensors, as desired.

The fluid circuit may also include a leukocyte reduction filter in flowcommunication with a separator outlet fluid flow path, for example, forremoving leukocytes from concentrated red cells collected by theseparator. The leukocyte reduction filter may also reduce the numberplatelets contained with the red cells. The durable controller controlsystem may be programmed to prime the fluid circuit with cellpreservation solution before processing whole blood and, if desired, toflush the fluid circuit of whole blood and/or red cells aftersubstantially all the whole blood is processed, in order to increase theefficiency or maximize the collection of red cells from the unit ofwhole blood.

As described in more detail below, the durable controller may alsoinclude a drive unit for causing relative rotation between the house andthe rotor to create Taylor-Couette flow conditions in the gap betweenrotor and housing. More specifically, the relative rotational speeds andthe width of the gap between the facing surfaces of the rotor andhousing may be such as to create Taylor vortices in the gap, whichvortices act to continuously sweep the membrane free of accumulatedcells, allowing increased flow of plasma through the membrane and,consequently, reduce processing time for processing a unit of wholeblood.

Further, in connection with the subject matter described herein apre-assembled disposable fluid flow circuit is described for separatingwhole blood into a plasma component and a concentrated red component.The fluid flow circuit, is preferably pre-assembled and pre-sterilized,and includes a whole blood fluid flow path with a whole blood inlet forconnection to a container containing a collected unit of whole blood,and a cell preservation solution flow path with an inlet for connectionto a source of cell preservation solution, such as Adsol® solutionreferred to earlier. The fluid circuit includes a separator with anouter housing and an inner rotor mounted within the housing for rotationrelative to the housing, with a gap defined between the outer surface ofthe rotor and an inner surface of the housing. At least one of the inneror outer surfaces of the housing and rotor, respectfully, comprises afilter membrane configured to allow passage of plasma therethrough whilesubstantially blocking red cells. The outer housing includes an inlet influid communication with the whole blood and/or cell preservationsolution flow paths and in flow communication with the gap between theinterior rotor and the outer housing, for directing whole blood and/orcell preservation solutions into the gap. The housing includes a firstoutlet communicating with the gap, for example, for removingconcentrated red cells from the gap. The housing and/or the rotor alsomay include a second outlet communicating with the side of membranefacing away from the gap for collecting fluid that passes through themembrane, such as plasma. The first and second outlets are proximate toa top portion of the housing and/or rotor, while the inlet is proximateto a bottom portion of the housing. Further, the first housing outletthat communicates with the gap is preferably in flow communication withan outlet fluid flow path for connection to a red cell storage containerwhich may be pre-assembled and pre-attached to the rest of the fluidcircuit if desired.

Further, the pre-assembled disposable fluid flow circuit may include aleukocyte reduction filter in flow communication with the outlet fluidflow path, for reduction of leukocytes in the concentrated red cells. Ifdesired, a leukocyte reduction filter could also be provided in a flowpath communicating with a side of the membrane facing away from the gapfor filtering fluid passing through the membranes, such as plasma.Optionally the pre-assembled disposable fluid circuit may also include apre-attached container of red cell or other cell preservation solution,such as a Fenwal Adsol® solution.

In another aspect of the disclosure, a disposable fluid circuitconfigured to interface with a hardware component to form an automatedblood collection system for collecting red blood cells and plasma from adonor comprising is provided. The disposable component includes a donoraccess device for withdrawing whole blood from a donor, with a wholeblood collection container in communication with the donor access devicefor receipt of whole blood from a donor. The circuit further includes ablood separation device communicating with the whole blood collectioncontainer and employing relatively rotating surfaces, with at least oneof the surfaces carrying a membrane substantially permeable to plasmaand substantially impermeable to red blood cells to separate the wholeblood into substantially concentrated red cells and plasma. A firstcollection container is provided that communicates with the bloodseparation chamber for receipt of the substantially concentrated redblood cells, with a source of preservative solution communicating withthe first collection container. A second collection containercommunicating with the blood separation chamber is provided for receiptof the plasma.

In another aspect, the disposable fluid circuit includes a leukocytefilter communicating with the first collection container. Further, thesource of the preservative solution and the whole blood collectioncontainer and donor access device may either be formed integrally withthe fluid circuit, or formed separately from the fluid circuit and areconfigured to be attached thereto.

In a further aspect of the disclosure, a method for collecting red bloodcells using a spinning membrane separation device is provided in whichan increased volume of red blood cells may be collected. Pursuant to themethod, a first quantity of whole blood is withdrawn from the donor. Thefirst quantity of whole blood is then separated into a first quantity ofred blood cells and a first quantity of plasma using the spinningmembrane separator. The first quantity of separated red blood cells andthe first quantity of separated plasma are then flowed to respectivecollection containers. Then, at least a portion of the first quantity ofseparated plasma is returned to the donor. Optionally, the whole bloodmay be flowed into a processing container before being flowed to thespinning membrane separation device so as to permit the return of plasmato the donor simultaneously with the separation of whole blood into redblood cells and plasma. A second quantity of whole blood is thenwithdrawn from the donor and separated into a second quantity of redblood cells and a second quantity of plasma using the spinning membraneseparator. The second quantities of red blood cells and plasma areflowed to the respective collection containers, and at least a portionof the second quantity of red blood cells, and at least a portion of thesecond quantity of plasma is returned to the donor

In another aspect, the spinning membrane separator is primed prior towithdrawing whole blood from the donor. Further, after at least aportion of the second quantity of plasma is returned to the donor,saline may also be returned to the donor. If a filter is used forleukoreduction of the separated red blood cells, the filter may beflushed with additive solution after the total desired volume of redblood cells is collected.

In accordance with another aspect of the present disclosure, a fluidprocessing circuit for the collection of leukoreduced red blood cells.The circuit includes a blood separator for separating red blood cellsfrom whole blood. The separator has a membrane configured to spin abouta generally vertically-oriented axis within a housing which includes anupper end region and a lower end region in the operating position. Theseparator also includes a red blood cell outlet in the upper end regionof the housing and a whole blood inlet in the lower end region of thehousing. The circuit further includes an additive solution flow pathconnecting a source of additive solution to the whole blood inlet and ared blood cell flow path connecting a leukoreduction filter to the redblood cell outlet. A red blood cell collection container is connected tothe leukoreduction filter for collecting red blood cells after passagethrough the leukoreduction filter. The system also includes another orsecond flow path for additive solution that connects the source ofadditive solution to the red blood cell flow path at a junction upstreamof the leukoreduction filter. The additive solution is mixed with redblood cells prior to passage through the leukoreduction filter.

In accordance with yet another aspect, a method for collectingleukoreduced red blood cells that employs a spinning membrane separatorincluding a membrane configured to spin about a generallyvertically-oriented axis within a housing. The housing includes an upperend region and a lower end region in the operating position. Theseparator also includes a red blood cell outlet in the upper end regionof the housing and a whole blood inlet in the lower end region of thehousing. The method includes flowing additive solution into the wholeblood inlet of the housing to prime the separator. Whole blood is flowedinto the whole blood inlet of the housing wherein red blood cells areseparated from the whole blood. The separated red blood cells flow outof the red blood cell outlet of the housing and are combined withadditive solution. The separated red blood cells and additive solutioncombination are passed through a leukoreduction filter and collected.

In accordance with yet another aspect, a system for separating bloodincludes a blood separator for separating red blood cells from wholeblood and a leukoreduction filter that filters leukocytes from the redblood cells as the red blood cells pass through the filter. The systemalso includes a pump that pumps additive solution through theleukoreduction filter to flush remaining red blood cells from the filterafter filtration. The pump increases the flush rate of the additivesolution through the leukoreduction filter during flushing of thefilter.

In accordance with a further aspect, a blood processing system includesa leukoreduction filter for removing leukocytes from red blood cells asthe red blood cells pass through the filter and a pump for pumping anadditive solution through the leukoreduction filter to flush theleukoreduction filter of red blood cells that remain in theleukoreduction filter after filtration of the red blood cells. The pumpcontrols the flush rate of the additive solution through the filter andvaries the flush rate of the additive solution during flushing of theleukoreduction filter.

In accordance with another aspect, a method of flushing a leukoreductionfilter includes flowing additive solution through the leukoreductionfilter at an initial flush rate to flush remaining red blood cells fromthe leukoreduction filter and increasing the flush rate of theleukoreduction filter during flushing of the filter.

In accordance with yet another aspect, a method of creating an additivesolution flush rate ramp-up schedule for flushing a leukoreductionfilter. The method includes forming a first correlation betweenhematocrit and hemolysis at selected additive solution flush ratesthrough the leukoreduction filter and forming a second correlationbetween hematocrit decay and the time it takes to decay hematocrit atthe selected additive solution flush rates through the leukoreductionfilter. The first and second correlations are used to determine theadditive solution flush rate ramp-up schedule.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the present subject matter are described inthe following detailed description and shown in the attached figures, ofwhich:

FIG. 1 is a perspective view a spinning membrane separator, in partialcross section and with portions removed to show detail.

FIG. 2 is a longitudinal cross sectional view of the spinning membraneseparator of FIG. 1.

FIG. 3 is a contour plot of outlet hematocrit and outlet wall shearstress as a function of relative filtration length and spinner radiusbased on a theoretical design model.

FIG. 4 is a contour plot of outlet hematocrit and outlet plasmahemoglobin concentration as a function of relative filtration length andspinner radius based on a theoretical design model for which themembrane tangential velocity is constant.

FIG. 5 is a contour plot of outlet hematocrit and Taylor number as afunction of relative filtration length and spinner radius based on atheoretical design model.

FIG. 6 is a three-dimensional plot of plasma hemoglobin concentration asa function of relative filtration length and spinner radius based on atheoretical design model.

FIG. 7 is a perspective view of a spinning membrane device or separatoraccording to the present application.

FIG. 8 is a schematic cross sectional view of a spinning membraneseparator in accordance with the present application in which thespinner includes a radially-extending ridge for defining separate fluidregions.

FIG. 9 is a schematic view of an automated whole blood separation systemfor processing previously-collected whole blood including a disposablefluid flow circuit module and a durable controller or control modulewith the fluid flow circuit module assembled thereon.

FIG. 10 is a flow diagram showing one embodiment of fluid flow through afluid flow circuit as described herein for processing a unit of wholeblood into a concentrated red cell product and a plasma product.

FIG. 11 is similar to FIG. 9 but a somewhat more detailed view ofcomponents of a disposable fluid flow circuit or module and a durablecontroller module.

FIG. 12 is a schematic view of an alternate embodiment of the systemaccording to the present disclosure in which the system is used for theseparation of previously-collected whole blood.

FIG. 12A is a schematic view of a further alternate embodiment, similarto FIG. 12.

FIGS. 12B-12E are schematic views of a further embodiment alternative tothose of FIGS. 9, 11 and 12.

FIG. 13 is a perspective view of a two-pump blood separation system suchas that shown in FIGS. 9, 11, 12 and 12A.

FIG. 14 is a schematic view of a further alternative similar to FIG. 12,except incorporating three pumps, illustrating the system in the primingphase.

FIG. 15 is a schematic view of the system of FIG. 14 illustrating thesystem in the separation phase.

FIG. 15A is a schematic view of a further alternative three-pump system,similar to FIGS. 14 and 15.

FIG. 15B is a schematic view of yet a further alternative three-pumpsystem.

FIG. 15C is a schematic view of the system of FIG. 15B illustrating thesystem in the separation and collection phase.

FIG. 15D is a schematic view of the testing system used in the Example.

FIG. 15E is a graphical representation of the hemolysis vs. thehematocrit of the various tests of the Example.

FIG. 15F is a graphical representation of the normalized hematocrit vs.flush time of the various tests of the Example.

FIG. 15G is a graphical representation of flow rate increases based onthe first and second correlations of the Example.

FIG. 15H is a graphical representation illustrating the determination ofwhich flow rate to use when the hematocrit reaches or decays to 50%.

FIG. 15I is a graphical representation illustrating the determination ofthe time it takes for the hematocrit to decay from 88% to 50% at a flushrate of 22 ml/min.

FIG. 15J is a graphical representation illustrating the determination ofwhich flow rate to use when the hematocrit reaches or decays to 40%.

FIG. 15K is a graphical representation illustrating the determination ofthe time it takes for the hematocrit to decay from 50% to 40% at a flushrate of 30 ml/min.

FIG. 16 is a schematic view of an automated whole blood collectionsystem according to the present disclosure showing the configuration ofthe system for automated chairside collection and processing of wholeblood from a donor in the priming mode.

FIGS. 16A-16D show various alternative disposable fluid circuits inaccordance with the present disclosure.

FIG. 17 is a schematic view of the system of FIG. 16 showing theconfiguration of the system for collecting and separating whole bloodinto red blood cells and plasma.

FIG. 18 is a schematic view of the system of FIG. 16 showing theconfiguration of the system for rinsing the system with anticoagulantafter the completion of blood collection from the donor.

FIG. 19 is a schematic view of the system of FIG. 16 showing theconfiguration of the system at the end of the blood collectionprocedure.

FIG. 20 is a schematic view of the system of FIG. 16 showing theconfiguration of the system in the optional arrangement for filteringthe collected red blood cells through a leukocyte filter.

FIG. 21 is a schematic view of an alternate embodiment of an automatedwhole blood collection system to that of FIGS. 16-20 in which thesingle-use disposable fluid circuit component comprises an integralleukoreduction filter as part of the draw line of the donor accessdevice.

FIG. 22 is a schematic view of an alternative embodiment of thesingle-use disposable fluid circuit of FIG. 21 in which theleukoreduction filter is positioned in the draw line downstream from theentry point where anticoagulant is introduced into the whole blood.

FIGS. 22A and 22B are schematic views of a further alternate embodimentof an automated whole blood collection system configured to be utilizedfor the collection of an increased volume of red blood cells.

FIGS. 22C-22I illustrate the system of FIGS. 22A and 22B in variousstages of operation.

FIGS. 22J and 22K and are schematic views of an embodiment of anautomated whole blood collection system for the collection of anincreased volume of red blood cells that allows for the simultaneousseparation of whole blood and the return of plasma to the donor.

FIGS. 22L, 22M, and 22N illustrate embodiments of disposable fluidcircuits for use in the systems of FIGS. 22A, 22I, and 22J,respectively.

FIG. 23 shows a disposable set useful in the washing of cells inaccordance with the method disclosed herein.

FIG. 24 shows another embodiment of a disposable set useful in thewashing of cells in accordance with an alternative method disclosedherein.

FIG. 25 shows an embodiment of the control panel of a device useful inthe washing of cells in accordance with the method disclosed herein.

FIGS. 26-28 are flowcharts of the steps in the method cell washingdisclosed herein.

FIG. 29 is a flow chart illustrating a data management method inaccordance the present disclosure.

FIG. 30 is a schematic drawing of a data management system according tothe present disclosure in combination with a collection container and aprocessing kit.

FIG. 31 is a flow chart illustrating the various steps comprising amethod for data management in accordance with the present disclosure.

DETAILED DESCRIPTION

A more detailed description of the spinning membrane separator inaccordance with the present disclosure and its use in various automatedsystems is set forth below. It should be understood that descriptionbelow of specific devices and methods is intended to be exemplary, andnot exhaustive of all possible variations or applications. Thus, thescope of the disclosure is not intended to be limiting, and should beunderstood to encompass variations or embodiments that would occur topersons of ordinary skill.

Turning to FIGS. 1 and 2, a spinning membrane blood separation orfractionation system, generally designated 10, is shown. Such a system10 is typically used to extract plasma from whole blood obtained from anindividual human donor. For ease of understanding, only the plasmaseparation device and the associated drive unit are shown, although itshould be understood that such a separator forms part of a disposablesystem including collection bags, bags of additives such as saline orACD, return bags, tubing, etc., and that there are also associatedcontrol and instrumentation systems for operation of the device.

The system 10 includes a generally cylindrical housing 12, mountedconcentrically about a longitudinal vertical central axis. An internalmember 14 is mounted concentric with the central axis. The housing andinternal member is relatively rotatable. In the preferred embodiment, asillustrated, the housing is stationary and the internal member is arotating spinner that is rotatable concentrically within the cylindricalhousing 12. The boundaries of the blood flow path are generally definedby the gap 16 between the interior surface of the housing 12 and theexterior surface of the rotary spinner 14. The spacing between thehousing and the spinner is sometimes referred to as the shear gap. Atypical shear gap may be approximately 0.025-0.050 inches (0.067-0.127cm) and may be of a uniform dimension along the axis, for example, wherethe axis of the spinner and housing are coincident. The shear gap mayalso vary circumferentially for example, where the axis of the housingand spinner are offset.

The shear gap also may vary along the axial direction, for examplepreferably an increasing gap width in the direction of flow to limithemolysis. Such a gap width may range from about 0.025 to about 0.075inches (0.06-0.19 cm). For example the axes of the housing and rotorcould be coincident and the diameter of the rotor decrease in the axialdirection (direction of flow) while the diameter of inner surface of thehousing remains constant or the diameter of the housing increases whilethe rotor diameter remains constant, or both surfaces vary in diameter.For example the gap width may be about 0.035 inches (0.088 cm) at theupstream or inlet end of the gap and about 0.059 inches (0.15 cm) at thedownstream end or terminus of the gap. The gap width could be varied byvarying the outer diameter of the rotor and/or the inner diameter of thefacing housing surface. The gap width could change linearly or stepwiseor in some other manner as may be desired. In any event, the widthdimension of the gap is preferably selected so that at the desiredrelative rotational speed, Taylor-Couette flow, such as Taylor vortices,are created in the gap and hemolysis is limited.

Whole blood is fed from an inlet conduit 20 through an inlet orifice 22,which directs the blood into the blood flow entrance region in a pathtangential to the circumference about the upper end of the spinner 14.At the bottom end of the cylindrical housing 12, the housing inner wallincludes an exit orifice 34.

The cylindrical housing 12 is completed by an upper end cap 40 having anend boss 42, the walls of which are nonmagnetic, and a bottom endhousing 44 terminating in a plasma outlet orifice 46 concentric with thecentral axis.

The spinner 14 is rotatably mounted between the upper end cap 40 and thebottom end housing 44. The spinner 14 comprises a shaped central mandrelor rotor 50, the outer surface of which is shaped to define a series ofspaced-apart circumferential grooves or ribs 52 separated by annularlands 54. The surface channels defined by the circumferential grooves 52are interconnected by longitudinal grooves 56. At each end of themandrel 50, these grooves 56 are in communication with a central orificeor manifold 58.

In the illustrated embodiment, the surface of the rotary spinner 14 isat least partially, and is preferably substantially or entirely, coveredby a cylindrical porous membrane 62. The membrane 62 typically has anominal pore size of 0.6 microns, but other pore sizes may alternativelybe used. Membranes useful in the washing methods described herein may befibrous mesh membranes, cast membranes, track etched membranes or othertypes of membranes that will be known to those of skill in the art. Forexample, in one embodiment, the membrane may have a polyester mesh(substrate) with nylon particles solidified thereon, thereby creating atortuous path through which only certain sized components will pass. Inanother embodiment, the membrane may be made of a thin (approximately 15micron thick) sheet of, for example, polycarbonate. In this embodiment,pores (holes) may be larger than those described above. For example,pores may be approximately 3-5 microns. The pores may be sized to allowsmall formed components (e.g., platelets, microparticles, etc.) to pass,while the desired cells (e.g., white blood cells) are collected.

The rotary spinner is mounted in the upper end cap to rotate about a pin64, which is press fit into the end cap 40 on one side and seated withina cylindrical bearing surface 65 in an end cylinder 66 forming part ofthe rotary spinner 14. The internal spinner or outer housing may berotated by any suitable rotary drive device or system. As illustrated,the end cylinder 66 is partially encompassed by a ring 68 of magneticmaterial utilized in indirect driving of the spinner 14. A drive motor70 exterior to the housing 12 is coupled to turn an annular magneticdrive member 72 that includes at least a pair of interior permanentmagnets 74. As the annular drive member 72 is rotated, magneticattraction between the ring 68 interior to the housing 12 and themagnets 74 exterior to the housing locks the spinner 14 to the exteriordrive, causing the spinner 14 to rotate.

At the lower end of the rotary spinner 14, the central outlet orifice 58communicates with a central bore 76 in an end bearing 78 that isconcentric with the central axis. An end bearing seat is defined by aninternal shoulder 80 that forms a lower edge of a central opening 82.The central opening 82 communicates with the plasma outlet orifice 46.If the inner facing surface of the housing is covered entirely orpartially by a membrane, a fluid collection or manifold may be providedbeneath the membrane to collect plasma and direct it through a housingoutlet (not shown).

I. Membrane Separator Design

In keeping with one aspect of the application, a spinning membraneseparator is provided that provides for improved plasma flow rates withan acceptably low level of hemolysis in the retained blood. Variousfactors are known to affect the filtration flow rate through spinningmembrane separators, including the speed of rotation, the size of thegap between the spinning membrane and the shell, the effective area ofthe membrane, the concentration of red blood cells (or hematocrit), andthe blood viscosity. Previous practices in the design of spinningmembrane devices have been largely empirical, aided to some extent byvague phenomenological descriptions of the effects of the various designparameters on performance and hemolysis. This has proved to beinefficient in terms of development time and technical resources spent.

In contrast, the parameters of the spinning membrane separator of thepresent application were determined based on quantitative differentialmodels that take into account the local plasma velocity through themembrane and the local hemoglobin concentration. These differentialmodels were integrated over the length of the device to provide a totalplasma flow rate and plasma hemoglobin concentration at the outlet ofthe device.

The method included the operational inputs based upon the existingPlasmacell-C separator geometry and operating conditions, includingdonor hematocrit, inlet blood flow rate, rotational speed, and effectivemembrane area. Also factored in were the geometric inputs of rotorradius, the width of the annular gap, and the length over which theintegration is performed. See Table 1 below. To obtain predicted valuesfor hypothetical separators, rotor radius and filtration length werevaried from about 1.0 to up to about 2.0 times the current Plasmacell-Cvalues in increments of 0.05, providing a 21×21 design space grid foreach output variable of interest. For all devices, the housing taper andthe gap at the outlet were held constant, and the inlet gap androtational speed were varied accordingly. Models were also developedwhich related blood viscosity and density to hematocrit, temperature,and anticoagulant concentration.

TABLE 1 Inputs for Model Calculations Parameter, units Value Inlet bloodflow rate, ml/min 106 Inlet hematocrit, % 42 Temperature, ° C. 35Citrate concentration, % 5.66 Filtration length, in 2.992 Rotor radiuswith membrane, in 0.5335 Inlet gap, in 0.0265 Outlet gap, in 0.0230Effective membrane fraction 0.50 Width of membrane bonding area, in 0.18Rotation speed, rpm 3600 Wall hematocrit, % 0.90 Red cell radius, μm2.75 Red cell hemoglobin concentration, 335.60 mg/dL Density of plasma,g/cm3 1.024 Density of packed red cells, g/cm3 1.096 Viscosity ofcitrated plasma, cP 1.39

In one implementation of the method, outputs of plasma flow rate andhemoglobin concentration were obtained for various values of the rotorradius, the rotational speed, and the integration length. The results ofthe models are shown in superimposed contour plots of the outlethematocrit and outlet wall shear stress (FIG. 3), the outlet hematocritand the outlet plasma hemoglobin concentration (FIG. 4), and the outlethematocrit and Taylor number (FIG. 5), all as a function of the relativefiltration length and spinner radius. (The “Taylor number” is adimensionless quantity that characterizes the inertial forces due torotation of a fluid about an axis relative to viscous forces.) As usedherein, “filtration length” is understood to be axial length of thecentral mandrel or rotor 50 from the beginning to the end of grooves orribs 52. It generally represents the length of the membrane availablefor filtration. The “spinner radius” or “spinner diameter” is understoodto be the radius or diameter of the rotor with the membrane attached.FIG. 6 shows the plasma hemoglobin results as a function of filtrationlength and spinner radius in a three-dimensional plot, showing theincrease in hemoglobin with larger devices. These results were thenevaluated to provide the best balance of high plasma flow rate withacceptably low levels of hemolysis.

The models indicated that the effective area of the membrane has thestrongest positive influence on performance. Further, while increasingthe membrane area by increasing the diameter of the rotor morepositively impacts flow rates than increasing the membrane area byincreasing the length of the rotor, it also increases the potential forhemolysis due to the increased velocity of the membrane, and thus theincrease in shear forces in the gap.

Accordingly, the models predicted lengths and diameters for the rotorthat would result in increased membrane areas whose use would also haveacceptably low levels of hemolysis. Prototype separators (based on theresults of the models) were made and tested to validate the resultspredicted by the models. Table 2, below, compares a current Plasmacell-Cplasmapheresis device with two potential alternatives based on themodels.

TABLE 2 Device Parameter, units Plasmacell-C RL 140-162 RL 140-185Relative filtration length 1.00 1.62 1.85 Relative spinner radius 1.001.40 1.40 Relative spinner speed 1.00 0.70 0.75 Filtration length, in2.992 4.847 5.535 Spinner radius, in 0.5335 0.7469 0.7469 Spinner speed,rpm 3600 2520 2700 Inlet gap, in 0.0265 0.0287 0.0295 Outlet gap, in0.0230 0.0230 0.0230 Inlet flow rate, ml/min 106 106 106 Inlethematocrit, % 42 42 42 Citrate concentration, % 5.66 5.66 5.66 Plasmaflow rate. ml/min 36.33 47.42 50.57 Outlet hematocrit, % 63.90 76.0080.32 Outlet plasma hemoglobin 5.04 14.36 27.84 concentration, mg/dLResidence time, s 2.98 7.99 9.77 Centripetal pressure, mmHg 100.22 96.25110.50 Torque, in-oz 1.48 4.70 6.29 Outlet Taylor number 89.07 51.0046.96

With reference to Table 2 and FIG. 7, a spinning membrane separator 10includes a rotary spinner 14 which has a spinner diameter D, afiltration length FL, and an overall length LOA. In a typicalplasmapheresis device, such as the Plasmacell-C separator, the rotor hasa diameter D of approximately 1.1″, a filtration length FL, ofapproximately 3″, and an overall length, LOA, of approximately 5.0″.

In accordance with the present application, it has been found that thediameter of the membrane can be increased by up to about 2.0 times thediameter of the membrane found in a typical plasmapheresis device, whilethe length can be increased up to about 2.5 times the length of thespinning membrane in a typical plasma pheresis device. An increase inthe rotor size within these perimeters increases the filter membranearea sufficient to provide for a high plasma flow rate, while providingfor an acceptably low level of hemolysis. In a specific example, aspinning membrane separator according to the present application mayadvantageously have a diameter D of 1.65″, a filtration length FL of5.52″, and an overall length LOA of 7.7″.

Prototype spinning membrane separators were tested with bovine and humanblood to validate the results predicted by the models. Blood flow ratesof 100 ml/min were obtained with spinner speeds varying from 1000-3500rpm. Outlet hematocrit levels of 80% and higher were obtained beforehigh levels of fouling of the membrane were experienced. Collectiontimes for 880 ml of plasma ranged from between approximately 18 and 20minutes.

As noted above, the residence time of the red blood cells in the sheargap has a direct relationship to the amount of hemolysis. In spinningmembrane separation devices, flow regions exist along the axial lengthof the rotor where the fluid flows is relatively stagnant, resulting inpockets of hemolysis. To the extent that red blood cells from the highhemolysis region intermix with the flow in the low hemolysis region, thequality of the collected red blood cells is degraded.

Accordingly, in keeping with another aspect of the application, a methodis provided for creating separate fluid flow regions in the gap of aspinning membrane separator without the use of seals. The separate flowregions reduce or minimize the influence of mixing of the fluids betweenthe two flow regions. The separate flow regions are achieved by having araised rib or ridge in the gap to reduce or minimize the gap between thespinner and the outer cylinder. Preferably, the ridge or rib is providedon the surface of the rotor beyond where the spinning membrane isattached thereto.

The ridge is preferably located so as to define the boundary of the highperfusion flow region. The radial size of the ridge is inverselyproportional to the decree of mixing allowed between the two regionsdefined thereby, with a larger radial dimension for the ridge allowingfor less mixing. The axial dimension or extent of the ridge is alsoinversely proportional to the degree of mixing allowed, with a largeraxial dimension allowing for less mixing. The axial dimension of theridge is preferably at least one gap-size long to minimize the formationof adjacent Taylor vortices causing unwanted mixing.

With reference to FIG. 8, a schematic cross sectional representation ofa spinning membrane separation device 10 is shown. The device comprisesa fixed outer cylinder 12 and a rotating inner cylinder 14 having afilter member carried thereon. In accordance with the presentapplication, the inner cylinder is provided with a radial ridge 90. Thisridge serves to divide the gap 16 between the spinner and the outerhousing into two fluid regions. A first fluid region 92 has a stagnant,non-perfused region of flow, typically on the portion of the spinnerthat extends beyond the filter membrane. A second fluid region 94, whichtypically contacts the filter membrane, has a highly perfused region offlow.

Because the first fluid region 92 is not perfused, blood residingtherein is exposed to increased shear stresses for longer periods oftime than the blood in the second fluid region 94. Thus, the blood inthe first fluid region 92 may often become hemolyzed and has highconcentrations of free hemoglobin (Hb). The ridge 90 inhibits fluid flowbetween the two fluid regions, thus minimizing the extent of mixing ofthe Hb-contaminated blood in the first region 92 with the low Hb bloodin the second region 94.

While the ridge 90 is shown as being integral with the rotor, it couldalso be formed on the inside of the outer cylinder to achieve the sameeffect. As noted above, the axial dimension of the ridge should be atleast one-gap size long. A typical spinning membrane separation devicefor performing plasmapheresis typically has a gap between the spinnerand the containment wall of from 0.023″ to 0.0265″, and a ridge inaccordance with the present application could have an axial dimensionwithin the same general range. However, larger axial dimensions for theridge will result in reduced mixing and, in one example, a rotor havinga radially-extending ridge with an axial dimension of 0.092″ has beenfound to be effective.

II. Systems and Methods for Processing Previously Collected Whole Blood

A spinning membrane separation device as described above may beadvantageously used in various blood processing systems and methods forwhich prior devices generally were not suited, particularly systems andprocess for obtaining Red Blood Cells. In one type of system and method,the spinner may be used for “back lab” processing of previouslycollected whole blood, as shown in FIGS. 9-15A.

Turning now to FIG. 9, a disposable fluid flow circuit or module A and areusable durable controller or module B configured to cooperate with andcontrol flow through the fluid circuit A are schematically illustrated.The disposable fluid circuit A as illustrated in FIG. 9 includes variouscomponents interconnected by flexible plastic tubing defining flow pathsbetween the components. The circuit is preferably fully pre-assembledand pre-sterilized with the possible exception of the unit of wholeblood container and the cell preservative container. More specifically,the illustrated disposable circuit in FIG. 9 includes whole bloodcontainer 101, a cell preservation solution container 102, bloodcomponent separator 108, plasma collection container 112, optionalleukocyte reduction filter 113, and red cell collection container 115.While not illustrated in FIG. 9, the reusable module B may have hangerswith associated weigh scales for supporting any or all of the containers101, 102, 112 and 115. In various of the other embodiments discussedherein, such hangers/weigh scales may not be illustrated, but areunderstood to be part of the described systems.

The whole blood collection container 101 may be any suitable containerbut is typically a flexible plastic pouch or bag in which approximately450 ml of whole blood have been previously collected. The container 101may be part of a separate system during collection and then joined tothe rest of the fluid circuit A or actually part of the circuit A at thetime of collection. At the time collection, in accordance with customaryprocedure, the whole blood is mixed with an anticoagulant located in theprimary container to prevent premature coagulation. Accordingly, “wholeblood” as used herein includes blood mixed with anticoagulant.

Flexible plastic tubing 105 is attached to the whole blood collectioncontainer, such as by a sterile connection device or other suitableattachment mechanism, and defines a whole blood fluid flow path betweenthe whole blood container 101 and a junction with cell preservativesolution tubing 103, which extends from the cell preservation solutioncontainer 102 to the flow path junction. The flow path junction betweenthe whole blood flow path and all preservative flow path is located atinlet clamp 116. From the junction, the flow path extends through tubing107 to an inlet port in the separator 108.

As shown in FIG. 9 of this description, the separator housing has anoutlet that communicates with the gap between the housing and rotor andwith concentrated red cell flow path tubing 110 for withdrawingconcentrated red cells from the separator gap. In addition, the housingincludes an outlet from the rotor that communicates with the side of themembrane facing away from the gap (for example, the interior of therotor) and communicates with plasma flow path tubing 111.

For reducing the number of leukocytes that may be present in the redcells, the disposable fluid flow circuit A optionally includes aleukocyte reduction filter 113, which may be of any suitable well knownconstruction for removing leukocytes from concentrated red cells withoutunduly causing hemolysis of red cells or reducing the number of redcells in the collected product. The concentrated red cells flow from theleukocyte reduction filter 113 through a continuation 114 of theconcentrated red cell flow path into storage container 15 which may beof any suitable plastic material compatible with red cell storage.

The reusable or durable controller module B, as shown in the FIG. 9schematic, preferably includes a hematocrit sensor 104 for detecting thehematocrit and the whole blood flowing from the whole blood container101. The hematocrit detector may be of any suitable design orconstruction but is preferably as described in U.S. Pat. No. 6,419,822,which is hereby incorporated by reference.

The durable reusable controller or control module B also includes aninlet clamp 116 which may be operated to control fluid from the wholeblood container 101 or the cell preservative container 102 or,optionally, simultaneously and proportionally from both of thecontainers 101 and 102. For controlling flow of blood into theseparator, the reusable module includes an inlet pump 106, which alsomay be of any suitable construction, and may be, for example, aperistaltic type pump which operates by progressive compression orsqueezing of the tubing 107 forming the inlet flow path into theseparator, a flexible diaphragm pump or other suitable pump. A pressuresensor 117 communicates with the inlet flow path between the pump 106and the separator 108 to determine the inlet pumping pressure. Thesensor may output to the control system to provide an alarm function inthe event of an over-pressure condition or an under-pressure conditionor both.

To control the flow rate of concentrated red cells from the separator108, the reusable module also includes an outlet pump 109 that isassociated with the outlet flow path 110, and functions in the mannersimilar to that described with respect to inlet pump 106. It also may beof any suitable construction such as a peristaltic pump, a flexiblediaphragm or other suitable pumping structure. The plasma flow path 111exiting the separator is preferably not controlled by a pump, and thevolumetric flow rate through the plasma flow path tubing is thedifference between the inlet volumetric flow rate from pump 106 and theoutlet volumetric flow rate from pump 109. Reusable module B may,however, also include a clamp 118 for controlling flow of plasma throughthe plasma flow path tubing 111.

The disposable module A may also include a plasma collection container112 in fluid communication with the plasma flow path for receivingplasma separated by the separator 108. Because the plasma passes througha porous membrane in the separator 108, the plasma that is collected incontainer 112 is largely cell free plasma and may be suitable foradministration to patients, freezing for storage or subsequentprocessing.

FIG. 10 generally shows the flow path(s) of fluid through the systemillustrated in FIG. 9. Specifically, it shows flow of whole blood fromthe single unit whole blood container 101 through the whole bloodhematocrit detector 104, to a junction in the flow path located at thebinary clamp 116. Cell preservation solution, such as a red cellpreservation solution, flows from the red cell container 102 also to thejunction at the binary clamp 116. Depending on the processing stage, thebinary clamp allows the flow of whole blood or cell preservativedownstream into the remainder of the system. Optionally, the clamp 116could be a proportional clamp to allow a selected proportionate flow ofwhole blood and red cell preservative simultaneously.

From the binary clamp 116, the whole blood or cell preservative fluidflows through the inlet pump 106 and into the separation device 108. Asexplained earlier, the separation device employs a relatively rotatinghousing and rotor, at least one of which carries a membrane throughwhich plasma is allowed to pass. In one embodiment, the membrane iscarried on the surface of the rotor and plasma passes through themembrane and through internal passage labyrinth within the rotor exitingeventually to the plasma collection container 112. When the membrane ismounted on the rotor, the device is commonly referred to a spinningmembrane separator, as shown in FIG. 10. However, it should berecognized that the membrane could potentially be mounted on the insidesurface of the housing, facing the gap between the inside surface of thehousing wall and the outer surface of the membrane, or a membrane couldbe carried on both the outer surface of the rotor and the inner surfaceof the housing so that plasma flows through membranes simultaneously,therefore potentially increasing the separation speed or performance ofthe separator 108. From the separator 108, the concentrated red cellsflow through the housing outlet communicating with the gap between rotorand housing and through the red cell flow path 110 and the outlet pump109, which controls the volumetric flow rate of the concentrated redcells.

While the hematocrit of the concentrated red cells removed fromseparator 108 may vary, it is anticipated that the hematocrit of theconcentrated red cells will be approximately 80-85%. The outlet pump 109pumps the concentrated red cells into the red cell collection container115 and, optionally, through a leukocyte reduction filter located in thered cell flow path between the pump 109 and the collection container115. The force of the pump pushing the concentrated red cells throughthe leukocyte reduction filter helps to maintain the processing timewithin a reasonable range, as compared, for example, to the time itwould be required for gravity flow of concentrated red cells through aleukocyte reduction filter in a manual setting.

The plasma separated by the separator 108, as shown in the FIG. 10,flows from the separator device, for example, from an outletcommunicating with a labyrinth of passageways within the rotor through asingle control clamp 118 and to the plasma collection container 112. Asnoted earlier, because the plasma passes through the membrane, it islargely cell free and suitable for subsequent administration topatients, freezing, and/or for the processing, such as by fractionationto obtain plasma components for use in other therapeutic products. Thesystem could also include a filter such as a leukocyte reduction filterin the plasma flow line 111 if desired.

FIG. 11 illustrates one version of a potential system employing both adisposable fluid circuit module A and a reusable or durable controllermodule B. Although shown assembled, the fluid circuit module A anddurable module B have separate and independent utility and may be usedwith other systems as well. As can be seen in FIG. 11, the disposablemodule A is conveniently mounted to the face of the reusable module B,which has associated hangars or supports, some of which may beassociated with weight scales, for supporting the various containers ofthe disposable system. The disposable module is, as indicated earlier,preferably preassembled, and pre-sterilized. The cell preservativesolution container may be pre-attached as part of the disposable systemor may be added later, such as by a sterile connection device or othersuitable attachment. The whole blood container which contains the unitof previously collected whole blood may also be pre-attached to thepre-assembled fluid circuit or attached by way of a sterile connectiondevice or other suitable attachment mechanism.

The face of the reusable module B includes, in this embodiment, aseparate solution clamp 116 a for controlling flow of cell preservationsolution from the solution container 102, which is hung from an elevatedsolution support pole. The whole blood container 101 is hung from aweight scale. The weight scale may be of conventional construction andmay provide a weight measurement signal that may be used by the controlsystem of the module B for sensing the amount of whole blood thatremains in the container and/or the amount of whole blood that has beenprocessed through the system. The disposable system includes a red cellflow path 105 that extends from the whole blood container, through thehematocrit detector 104, and through a separate whole blood clamp 116 bfor controlling flow of whole blood from the container into the system.The cell preservative solution flow path 103 and the whole blood flowpath 105 combine at a junction, such as a v-site or y-site, upstream ofthe inlet pump 106. The combined flow path extends through the inletpump and to an inlet on the separator device 108. As is visible in FIG.11, the reusable module B includes a drive unit, such as a magneticdrive unit for causing rotation of the rotor within the separatorhousing without requiring drive members or components to physicallyextend through the housing. In this arrangement, the rotor includes amagnetically coupled drive element that is rotated by the magnetic driveunit associated with the reusable module. This system is described morefully in U.S. Pat. No. 5,194,145 to Schoendrofer, incorporated byreference herein.

The concentrated red cell outlet from the separator 108 is attached tothe red cell flow path 110, which extends through outlet pump 109 and toan inlet into the optional leukocyte reduction filter 113. Filter medialocated between the inlet and outlet of the leukocyte reduction filtersubstantially removes leukocytes from the red cells. From the filteroutlet, the red cell flow path tubing 114 conveys the red cells into thered cell collection container 115.

Plasma is conducted from the plasma outlet of the separator through aplasma flow control clamp 118 and into the plasma collection container112. In a manner similar to the whole blood container, the concentratedred cell container 115 and the plasma container 112 are suspended fromweight scales which may be in electronic communication with the controlsystem of the durable or reusable module B to provide informationregarding the amount of concentrated red cells and/or plasma collectedfrom the whole blood or the rate of collection.

While this system has been illustrated with certain basic components andfeatures as described above, this description is not intended topreclude the addition of other components, such as sensors, pumps,filters or the like as may be desired. For example, it may optionally bedesired to filter plasma before it enters the plasma collectioncontainer or to omit a leukoreduction filter for red cells. Although theplasma removed from the separator 108 is largely cell free, there may bea further desire to filter the plasma for reasons of subsequentadministration or processing. The present description is not intended topreclude the possible addition of further components or the deletion ofone or more of the components described above.

Turning now to the processing of whole blood in the illustrated system,the separation process begins by priming the system. “Priming” refers tothe method by which the filter membrane is prepared (i.e., wetted) priorto use. Wetting with a fluid helps to displace air present in the matrixof the membrane prior to pressure-induced fluid flow through themembrane. Typically, a low viscosity non-biological fluid, such as acell preservation solution (red cell solution such as, Adsol® solution)is used for wetting to allow the most effective displacement of air.During the prime, fluid is removed from the cell preservation solutionbag 102 by the inlet pump 106 until the solution line 103, whole bloodline 105, inlet line 107, and spinning membrane device 108 arecompletely filled with the solution. To ensure proper priming, the inletpump 106 may move both clockwise and counterclockwise during the prime.The purpose of the solution prime is to prevent an air-blood interfacefrom forming by creating a solution-blood interface and to wet themembrane within the separation device. Each is a measure taken to reducethe hemolysis of red blood cells.

After the system is successfully primed, the cell solution flow path 103will be closed by the inlet clamp 116. The illustrated inlet clamp is abinary clamp that can close either the cell preservation solution flowpath 103 or the whole blood flow path 107. Whole blood will then bepumped through the whole blood flow path 105 and the inlet flow path 107by the inlet pump 106 into the separator 108. Inlet pump 106 flow ratescan vary from about 10 ml/min to 150 ml/min depending on desired productoutcomes for a specific procedure. As the whole blood leaves the wholeblood container 101 it will pass through the whole blood hematocritdetector 104 which will generate an estimation of the whole bloodhematocrit through IR LED reflectance measurements. Details of thehematocrit detector are explained in U.S. Pat. No. 6,419,822 (Title:Systems and methods for sensing red blood cell hematocrit), incorporatedby reference. The whole blood hematocrit value is required for aninitial control algorithm of the illustrated system, but may not beessential in other systems.

After whole blood has filled the separator 108, the system will begin todraw plasma from the separator which separates the whole blood enteringthe spinning membrane device into a red cell concentrate and virtuallycell free plasma. Packed red blood cells at approximately 80-85%hematocrit will be pumped out of the separator 108 through the red cellflow path 110 and into the red blood cell leukofilter 113 by the outletpump 109. The outlet pump forces the packed red blood cells through thered blood cell leukofilter 113 and the red cell concentrate which exitsthe red blood cell leukofilter 13 through the red blood cell line 114and into the red blood cell product bag 115 will be successfullydepleted of white blood cells and also depleted of platelets. It is alsopossible to complete a whole blood automated separation without the useof a red blood cell leukofilter 113. In this case the red blood cellleukofilter 114 would be removed from the system and the red blood cellproduct 115 would not be depleted of white blood cells or platelets.

Throughout the procedure, plasma will flow through the plasma flow path111 into the plasma bag 112 at a flow rate equal to the differencebetween the inlet pump 106 flow rate and outlet pump 109 flow rate as iscurrently done in other spinning membrane separation applications likethat applied in the Autopheresis-C® instrument sold by Fenwal, Inc. Thepressure across the membrane generated by the offset in flow rates ismonitored by the pressure sensor 117. The pressure measurements are usedto control the plasma flow rate using the algorithm described in U.S.patent application Ser. No. 13/095,633, filed Apr. 27, 2011 (Title:SYSTEMS AND METHODS OF CONTROLLING FOULING DURING A FILTRATIONPROCEDURE) hereby incorporated by reference.

The system in FIGS. 9-11 will continue to separate packed red bloodcells and plasma until the whole blood bag 101 is empty as detected byair passing through the whole blood hematocrit detector 104. At thispoint the whole blood line 105 will be closed and the cell preservativesolution line will be opened by the inlet clamp 116 to start thesolution rinse or flush. During the solution rinse, preservativesolution will be removed from the solution bag 102 and pumped into theseparator 108 by the inlet pump 106. The plasma flow path 111 is closedby the plasma clamp 118 during the solution rinse. The solution rinse isused to flush any blood remaining in the system into the red blood cellproduct container 115. The solution rinse will also increase the redblood cell product container 115 volume to the level desired for properred blood cell storage. After the solution rinse is finished theseparation of the whole blood unit is complete.

Turning to FIG. 12, a further alternative two-pump system is shown. Thisembodiment differs from that in FIG. 9 primarily in that the fluid fromthe blood cell preservative solution is added after the red blood cellshave been separated from the whole blood. More particularly, acontainer/bag 101 containing previously-collected whole blood(preferably already combined with an anticoagulant) is connected to thedisposable system A through tubing segment 107 that leads to the bloodseparator 108. Pump 106 cooperates with tubing 107 to pump whole bloodto the separator 108. Container 102 containing the red blood cellpreservative additive solution is connected to the collection container115 for the separated red blood cells through tubing 114, through whichthe separated red blood cells are also directed to container 115 throughthe leukocyte filter 114.

Sterile connection of the containers 101, 102 to the disposable systemmay be accomplished by a number of different ways. Container 102 for theadditive solution may be supplied as part of the disposable system A,and may be joined to the remainder of the disposable (aftersterilization by, e.g., gamma or E-Beam processing) during finalpackaging after the remainder of the disposable has been sterilized (by,e.g., moist heat processing). Alternatively, the container 102 may beformed integrally with the remainder of the disposable. In a furtheralternative, both the container 102 and the whole blood container 101may be separate from the remainder of the disposable and connected atthe time of use through, e.g., sterile spike connections 170, shownschematically in FIG. 10. Such spike connections preferably include a0.2 micron filter to maintain sterility.

In another aspect of this embodiment, the tubing 103 connecting theadditive solution container 102 to the leukocyte filter 62 may also becooperatively engaged by the pump 109. Specifically, pump 109 may be adual pump head that flows both the additive solution and the red bloodcells exiting the separator 108 to control the flow rate of each basedupon the inside diameter of the tubings 103 and 110.

The embodiment of FIG. 12 also utilizes an additional pressure sensor117 b to monitor the back pressure from the leukocyte filter 113. Shouldthe back pressure become excessive, as in the event of filter occlusion,the sensor will act to control the flow rate in order to ensure that thedisposable does not rupture due to excessive pressure.

III. Membrane Priming

In keeping with another aspect of the disclosure, a method for priming amembrane filter is provided by which is more likely that the maximumamount of the surface area of the filter membrane is wetted, thusmaximizing the membrane area available for filtration/separation.Specifically, when a spinning membrane filter system is primed asdescribed above, with the spinning membrane oriented so that the axis ofrotation is substantially vertical, the wetting solution enters at thetop inlet port of the spinning separator, and gravity pulls the fluidtoward the outlet at the bottom of the separator. Under suchcircumstances, the surface tension of the priming fluid will form anair-fluid interface that may move unevenly across the membrane surface,creating disruptions. The result is that certain areas of the filtermembrane may not be wetted during priming, thus increasing the potentialfor air being trapped in the membrane matrix. The unwetted area of themembrane then becomes unavailable for separation, adversely affectingthe separation efficiency of the membrane, until sufficient pressure isgenerated to displace the air.

Accordingly, a method for priming a membrane separator is provided thatmore uniformly wets the membrane surface by providing a more uniformair-fluid interface during priming. To this end, priming fluid isintroduced into the separator so that it works against the force ofgravity as the fluid-air interface advances in an upward directionacross the surface of the membrane. This helps to ensure a more uniformwetting of the membrane, as the air displaced during priming is able tomove in a single direction without being trapped as the air-fluidinterface advances across the membrane.

Thus, according to this alternate method for priming, the priming fluidis introduced into the separator through a port at the bottom of theseparator. The priming solution advances upwardly in the housing of theseparator against the force of gravity to wet the surface of themembrane, with the air being expelled from the separator through a portat the top of the separator. While this “bottom to top” priming isdescribed in the context of a spinning membrane separator, it is alsoapplicable to any type of membrane separator that requires fluid primingprior to use.

With reference to FIGS. 9 and 12, the separator 108 is orientedvertically, so that the membrane separator and housing are relativelyrotatable to one another about a generally-vertical axis, with the portfor receiving the whole blood at the top of the separator and the portsthrough which the separated RBCs and plasma exit at the bottom of theseparator. Thus, according to one way for performing this alternativepriming method, and with reference to FIGS. 1 and 2, the primingsolution may be introduced through one of the exit orifice 34 or plasmaoutlet orifice 46 of the spinning membrane separator 10, while air isexpelled through the inlet orifice 22.

According to another way for performing this alternative priming method,and as seen in FIG. 12B, separator 108 may be inverted or upturned forpriming, so that the exit orifice 34 and plasma outlet orifice 46 are atthe top of the separator 10, and the inlet orifice 22 is at the bottomof the separator 108. As also illustrated in FIG. 12B, the systemincludes a sterile dock device 120 to connect the whole blood bag 101 tothe rest of the kit. The sterile dock device is explained in furtherdetail in U.S. Provisional Application Ser. No. 61/578,690, filed Dec.21, 2011, incorporated by reference herein and a copy of which isattached. As seen in FIG. 12C, the priming solution may be introducedthrough the inlet 22, with the fluid-air interface advancing upwardlyand air being expelled through either or both of the exit orifice 34 andthe plasma outlet orifice 46. After priming, separation of the wholeblood may commence. To this end, the separator 10 may be returned to itsoriginal orientation, with the inlet orifice 22 at the top and the exitorifice 34 and plasma outlet orifice 46 at the bottom. Preferably theupside-down configuration of the spinning membrane 108 is maintained,and separation commences, as illustrated in FIG. 12D, until the wholeblood bag 101 is emptied. The spinning membrane 108 is then preferablyflushed with preservative additive solution (from container 102) pumpedinto the spinning membrane 108 through inlet orifice 22 to flow the redblood cells left in the spinning membrane 108 into the red blood cellcollection container 115. The flush with additive solution is continueduntil the total volume of additive solution in the collection container115 meets requirements.

A further alternative in which the “bottom to top” priming of the bloodseparator 108 described above may be used is shown in FIG. 12A. Incontrast to FIG. 12, the inlet line 107 for the whole blood connects tothe lower port of the separator 108 (to which the outlet line 110 hadbeen attached in the embodiment of FIG. 12), while the outlet line 110is connected to the port at the top of the separator 108 (to which theinlet line 107 had been attached in the embodiment of FIG. 12). To primethe system of FIG. 12A, clamp 116B is opened and pump 106 activated toflow whole blood (preferably with anticoagulant added) through the inletline 107 so that it enters the separator 108 through the port at thelower end of the housing. As the whole blood fills the separatorhousing, air is expelled through the top port, to substantiallyeliminate all air from the device, and the filter membrane is wetted.

After priming is completed, the system continues to operate as shown inFIG. 12A to separate the whole blood into plasma, received in container112, and red blood cells, received in container 115. At the end of theseparation procedure, the separator may be rinsed with additive solutionfrom container 102.

Turning to FIGS. 14 and 15, a further alternative blood separationsystem according to the present disclosure is shown. The system of FIGS.14 and 15 is similar to that of FIGS. 9, 11, and 12 except that thedurable module B includes a third pump 119 for selectively flowingadditive solution to either the separator 108 during the priming phase(as shown in FIG. 14), or to the separated red blood cells during theseparation phase (as shown in FIG. 15). The system of FIGS. 14 and 15also includes a further clamp 120 for selectively permitting orpreventing flow of fluid (separated red blood cells and additivesolution) through the leukofilter 113 and into the red blood cellcontainer 115. Prior to priming, clamp 120 could briefly remain open andpump 109 could pump residual air from container 115 and filter 113,minimizing the amount of air remaining in container 115 at the end ofthe procedure. Like FIG. 12A, the system of FIGS. 14 and 15 employsbottom to top priming of the separator 108, except using additivesolution for the priming fluid instead of whole blood. During priming ofthe system, as shown in FIG. 14, air from the disposable system A ispushed to the whole blood container 101.

During the separation phase, the system is operated as shown in FIG. 15.At the conclusion of the separation phase, additive solution is pumpedto the separator 108 (as shown in the prime phase illustrated in FIG.14) to rinse the separator.

Turning to FIG. 15A, a further alternative system is shown. The systemof FIG. 15A is like that of FIGS. 14 and 15, in that the reusablecomponent B comprises three pumps 106, 109, and 119. However, the systemof FIG. 15A is similar to that of FIG. 12A, in that the inlet line 107for the whole blood is connected to the port at the bottom of theseparator 108, while the outlet line for the separated red blood cellsis connected to the port at the top of the separator. Thus, the systemof FIG. 15A, whole blood is used for priming the system, similar to thesystem of FIG. 12A.

FIGS. 15B and 15C show yet another alternative fluid processing circuitincluding a three-pump system. The disposable circuit A includes a wholeblood container 101, an additive solution container 102 (such as a cellpreservation solution container), a blood component separator 108 (shownin the operating position), plasma collection container 112, aleukoreduction filter 113, and red cell collection container 115.

A whole blood fluid flow path 105 is attached to the whole bloodcollection container 101 and provides a flow path between the wholeblood container 101 and a junction 121 which also is connected to flowpath 103 a for additive solution. First flow path 103 a for additivesolution extends from additive solution container 102 to junction 121.From junction 121, whole blood flow path 105 extends through a flow path107, which is a continuation of whole blood flow path 105, to an inletport 123 located in a lower end region 125 of the housing 127 ofseparator 108.

Separator housing 127 has an outlet port 129 in the upper end region 131thereof that communicates with the gap between the housing and rotor andwith concentrated red blood cell flow path 110 for withdrawingconcentrated red cells from the separator gap. In addition, separator108 includes another outlet 133 also located in upper region 131 ofhousing 127 which communicates with the side of the membrane facing awayfrom the gap (for example, the interior of the rotor) and communicateswith plasma flow path 111.

For reducing the number of leukocytes that may be present in theseparated red cells, the fluid circuit includes a leukocyte reductionfilter 113 connected to red blood cell flow path 110 between outlet 129and red blood cell collection container 115, i.e., downstream ofseparator 108 and upstream of container 115. The leukoreduction filtermay be of any suitable well known construction for removing leukocytesfrom concentrated red cells without unduly causing hemolysis of redcells or reducing the number of red cells in the collected product. Asecond flow path for additive solution 103 b connects additive solutioncontainer 102 to red blood cell flow path 110 at junction 121 a which isupstream of leukoreduction filter 113. The concentrated red cells flowfrom outlet 129 through red blood cell flow path 110, where the redblood cells are combined with additive solution, to leukoreductionfilter 113. The red blood cells then flow from the leukoreduction filter113 through a continuation 114 of the concentrated red cell flow path110 into storage container 115 which may be of any suitable plasticmaterial compatible with red cell storage.

The fluid processing circuit also includes a whole blood inlet clamp 116b which is operated to control fluid from the whole blood container 101and additive solution clamp 116 a for controlling flow of additivesolution from the solution container 102 to whole blood flow path 105.The fluid processing circuit preferably includes a hematocrit sensor 104for detecting the hematocrit of the whole blood flowing from the wholeblood container 101. The hematocrit detector may be of any suitabledesign described above. For controlling flow of whole blood and/oradditive solution into the separator, the fluid processing circuitincludes an inlet pump 106, which may be of any suitable construction,and may be, for example, a peristaltic type pump which operates byprogressive compression or squeezing of the tubing forming the wholeblood flow path into the separator, a flexible diaphragm pump or othersuitable pump. Optionally, a pressure sensor 117 communicates with thewhole blood flow path 107 between the pump 106 and the separator 108 todetermine the inlet pumping pressure. The sensor may output to thecontrol system to provide an alarm function in the event of anover-pressure condition or an under-pressure condition or both.

To control the flow rate of concentrated red cells from the separator108, the reusable module B also includes an outlet pump 109 that isassociated with the red blood cell outlet flow path 110, and functionsin a manner similar to that described with respect to inlet pump 106. Italso may be of any suitable construction such as a peristaltic pump, aflexible diaphragm or other suitable pumping structure. The reusablemodule B also includes a third pump 119 for selectively flowing additivesolution through the second flow path 103 b for additive solution andinto the red blood cell flow path 110 where the additive solution iscombine or mixed with the separated red blood cells prior to beingpassed or pumped through leukoreduction filter 113 and into red bloodcell container 115. The addition of additive solution to the separatedred blood cells in red blood cell flow path 110 dilutes the red bloodcells to a lower hematocrit before passage through leukoreduction filter113. Dilution of the separated red blood cells decreases filter pressurewhich reduces the risk of hemolysis of red blood cells.

Turning now to the processing of whole blood in the system illustratedin FIGS. 15B and 15C. Similar to FIG. 12A, the system of FIGS. 15B and15C employs bottom to top priming of the separator 108, except thatadditive solution is used for the priming fluid instead of whole blood.Turning to FIG. 15B, during priming, clamp 116 b is closed to preventwhole blood from flowing out of whole blood container 101 and into wholeblood flow path 105. Clamp 116 a is opened and additive solution isremoved from additive solution container 102 by inlet pump 106 untiladditive solution flow path 103 a, whole blood flow path 105/107 and thespinning membrane device of separator 108 are completely filled. Toensure proper priming, inlet pump 106 may move both clockwise andcounterclockwise during the prime. During priming of the system, clamp118 is closed and air from the disposable system A is pushed to the redblood cell container 102.

Referring to FIG. 15C after the system is substantially primed, clamp116 a is closed and clamp 116 b is opened. Whole blood will then bepumped through the whole blood flow path 105 and whole bloodcontinuation flow path 107 by the inlet pump 106 into separator 108.Inlet pump 106 flow rates can vary for example, from about 10 ml/min to150 ml/min depending on desired product outcomes for a specificprocedure. As the whole blood leaves the whole blood container 101 itwill pass through the whole blood hematocrit detector 104 which willgenerate an estimation of the whole blood hematocrit through IR LEDreflectance measurements.

After whole blood has filled the separator 108, the system will begin todraw plasma from the separator which separates the whole blood enteringthe spinning membrane device into a red cell concentrate and virtuallycell free plasma. Packed red blood cells at approximately 80-85%hematocrit will flow out of outlet port 129 of separator 108 and bepumped through the red cell flow path 110. Additive solution is pumpedby pump 119 into red blood cell flow path 110 where the additivesolution mixes with and preferably dilutes the red blood cells in flowpath 110. Outlet pump 109 and/or pump 119 force the packed red bloodcells diluted to a lower hematocrit with the additive solution throughthe leukoreduction filter 113. The red cells and additive solution exitleukoreduction filter 113, flow through the red blood cell line 114 andinto the red blood cell collection container 115.

Additionally, clamp 118 will be opened and throughout the procedure,plasma will flow through the plasma flow path 111 into the plasma bag112 at a flow rate equal to the difference between the inlet pump 106flow rate and outlet pump 109 flow rate as described above. The pressureacross the membrane generated by the offset in flow rates is monitoredby the pressure sensor 117. The pressure measurements are used tocontrol the plasma flow rate as described above.

The system will continue to separate packed red blood cells and plasmauntil the whole blood bag 101 is empty as detected by air passingthrough the whole blood hematocrit detector 104. At this point the clamp116 b will be closed and the additive solution line will be opened byclamp 116 a to start the solution rinse or flush. During the solutionrinse, additive solution will be removed from additive solutioncontainer 102 and pumped into separator 108 by the inlet pump 106. Theplasma flow path 111 is closed by the plasma clamp 118 during thesolution rinse. The solution rinse is used to flush any red blood cellsremaining in the separator into red blood cell flow path 110, throughleukoreduction filter 113 and into red blood cell collection container115.

Either simultaneous with the solution rinse or after the solution rinse,additive solution may be pumped by pump 119 through second flow path 103b, red blood cell flow path 110, and leukoreduction filter 113 to flushremaining red blood cells from filter 113. If the flushing processoccurs after solution rinse, clamp 116 a is closed to direct theadditive solution only into flow path 103 b. As the additive solutionpasses through leukoreduction filter 113, the additive solution flushesor rinses red bloods cells from the filter and into red blood cellcollection container 115. Additive solution flow or flush rates may varyfor example, from about 10 ml/min to 150 ml/min. Additionally, the flushrate may be constant during flushing or may be increased or decreased.

In the blood separation system illustrated in FIGS. 15B and 15C andother separation systems (including backroom and inline systems), redblood cells remain in the leukoreduction filter after the whole bloodseparation process and red blood cell collection processes arecompleted. As described above, in order to collect the remaining redblood cells, additive solution is passed through the leukoreductionfilter to flush or rinse the remaining red blood cells from theleukoreduction filter. Such flushing with additive solution also mayincrease the additive solution volume in the collected red blood cellproduct, if such increase in additive solution is desired or required tomeet product requirements.

If the flow or flush rate of the additive solution it too great duringthe flushing process, hemolysis of the red blood cells being flushedfrom the filter may occur. Filter hemolysis can occur anytime too highof a concentration of red blood cells is forced through the membrane ofthe filter at too fast of a rate. For example, after the separation andcollection processes of red blood cells have been completed, theresidual red blood cells remaining in the filter may be highly packedand have a hematocrit between about 70% and about 87%. If the flow rateor flush rate of the additive solution used to flush the filter is toohigh, pressure will build within the filter resulting in a highconcentration of red blood cells being forced through the filter,resulting in hemolysis of the red blood cells. One way to help preventhemolysis is to use an additive solution flush rate that is the same orsimilar (e.g., slightly lower or higher) to that of the red blood cellsflow rate during separation and collection. In one embodiment, the redblood cell flow rate and the additive solution flush rate are keptconstant at about 22 ml/min and the amount of additive solution used forflushing is between about 60 ml and about 80 ml. At a flush rate ofabout 22 ml/min it could take up to about 4 minutes or longer tocomplete the flushing process.

In an alternative embodiment, it has been found that the time it takesto flush the filter may be shortened by starting at an initial additivesolution flow or flush rate and then continuously or graduallyincreasing the flush rate as the filter is being flushed. As additivesolution pushes or flushes remaining red blood cells out of the filter,the hematocrit of the red blood cells within the filter decreases ordecays. When the hematocrit of the red blood cells decreases within thefilter, the flush rate of additive solution through the filter may beincreased with little risk of increasing hemolysis. The increase ofadditive solution flush rate may be gradual (step-wise increases) orcontinuous. The timing and amount of flush rate increase may be based onone or more factors or measurements, including but not limited to, thehematocrit of the red blood cells in the filter, the amount of hemolysisat the various flush rates and/or the pressure within the filter. Thefactors may be employed as a predictor used to develop a pre-determineflush rate increase schedule/program or may be measured in real-timewherein the flush rate is increased based on real-time measurements. Thepump used to pump the additive solution through the filter duringflushing may be any suitable variable flow pump. Such pumps may include,but are not limited to, peristaltic or flexible diaphragm pumps.

In one exemplary embodiment, a desired flush rate increase is determinedfor a particular filter type or design from a correlation orrelationship between hemolysis, hematocrit and flush rate of theadditive solution through the filter. In this embodiment, a firstcorrelation is made between selected flush rates and the amount ofhemolysis that occurs at different hematocrit concentrations for each ofthe selected flush rates. Hemolysis may be measured by any suitablemethod and in one embodiment, for example, is measured by theconcentration of plasma hemoglobin (PLH) of the supernatant of the redblood cell product exiting the filter. The first correlation can be usedto predict if use of a selected flush rate would result in a tolerableamount of hemolysis at a given hematocrit concentration. Moreparticularly, the correlation is used to determine the hematocrit towhich the red blood cells within the filter would have to decrease tobefore the additive solution flush rate could be increased whilemaintaining an acceptable amount of hemolysis.

A second correlation is made between the selected flush rates and thedecrease or decay of hematocrit concentration over time at the selectedflush rates. This second correlation can be used to predict the timerequired to dilute the red blood cell concentration within the filter toa particular hematocrit for a given flush rate. As described in moredetail in the example below, knowing that a particular hematocrit andflush rate results in an acceptable the amount of hemolysis and the timerequired at a particular flush rate to decrease the red blood cellconcentration to that particular hematocrit, allows for the flush rateto be ramped up each time a particular hematocrit is reached.

EXAMPLE

The following non-limiting Example illustrates various features andcharacteristics of the present subject matter, which is not to beconstrued as limited thereto.

In this Example, tests were conducted to determine a first correlationor relationship between selected additive solution flush rates and theamount of hemolysis that occurs at different hematocrit concentrationsfor each of the flush rates, and to determine a second correlationbetween the selected flush rates and the decrease or decay of hematocritconcentration over time at each of the selected flush rates. Asexplained in more detail below, the first and second correlations werethen used to determine flush rate increases during filter flushing.

The system schematically illustrated in FIG. 15D was used to conducteach of the tests of this Example. The system includes a red blood cellcontainer 143 including a supply of red blood cells at an initialhematocrit of at least 85% for the tests run in this Example. The systemalso included an additive solution container 102, a leukoreductionfilter 113 a and a red blood cell collection container 115 a. In eachrun, an Asahi Sepacell A-100 leukoreduction filter (supplied by AsahiMedical Co. of Japan) was used as the filter and Adsol (supplied byBaxter International of Illinois) was used as the additive solution.

A red blood cell flow path 145 was attached to the red blood cell supplycontainer 143 and provided a flow path to junction 147 which wasconnected to an additive solution flow path 103. Red blood cell clamp157 controlled the flow of red blood cells from red blood cell supplycontainer 113. From junction 147, red blood cell flow path 145 extendedthrough flow path 149 to leukoreduction filter 113 a. Additive solutionflow path 103 was attached to additive solution container 102 andprovided a flow path to junction 147. Additive solution clamp 159controlled the flow of additive solution from additive solution supplycontainer 102. An M2 pump 161 pumped red blood cells and additivesolution through flow path 149 and leukoreduction filter 113 a. Flowpath 151 connected leukoreduction filter 113 a to red blood cellcollection container 115 a. An in-line sample site 153 was located inflow path 151 for taking samples during flushing of the leukoreductionfilter 113 a. A pressure sensor 155 was located upstream of the filter113 a for monitoring the pressure in the system.

During each run, red blood cell clamp 157 was opened and additivesolution clamp 159 was closed so as to flow red blood cells through flowpath 145 and 149. Pump 161 pumped the red blood cells through theleukoreduction filter 113 a at a rate of 22 ml/min. Once the red bloodcell supply container 143 was empty, red blood cell clamp 157 was closedand additive solution clamp 159 was opened to allow the additivesolution to flow through flow path 103 wherein the pump rate was set ata selected flush rate for the particular run. After the additivesolution started to be pumped through the leukoreduction filter 113 a toflush the filter in-line samples of the red blood cell/additive solutionmixture exiting the leukoreduction filter 113 a were continuously takenin 5 ml test tubes at in-line sample site 153. The hematocrit andhemolysis of each sample were then measured. Hematocrit was measured bya spun-hematocrit test and hemolysis was measured by the concentrationof plasma hemoglobin in the supernatant (mg/dl). The tables below listthe results for each flush rate tested. In the test results, thenormalized hematocrit was calculated by dividing the measured hematocritof the sample by the initial hematocrit of the red blood cells supplyand multiplying the result by 100.

TABLE 1 Adsol Flush Rate 22 ml/min Initial Red Blood Cell SupplyHematocrit = 89.25 Time (s) HCT (%) HCT (%) Norm PLH (mg/dl) 0 89.25 100418.3 15.74 89.5 100.280112 399.7 25.74 65.5 73.38935574 120.9 33.64 4550.42016807 64.3 42.84 39.25 43.97759104 46.6 55.04 33.5 37.53501401 3566.74 31.75 35.57422969 20 79.44 22 24.64985994 20.3 94.84 1820.16806723 15.2 117.24 14.15 15.85434174 12

TABLE 2 Adsol Flush Rate 30 ml/min Initial Red Blood Cell SupplyHematocrit = 85 Time (s) HCT (%) HCT (%) Norm PLH (mg/dl) 0 83.7598.52941176 244.5 17.02 83.5 98.23529412 255.9 26.63 52.75 62.0588235377.8 35.2 34.75 40.88235294 42.1 44.1 30.75 36.17647059 35.9 55.25 26.531.17647059 26 66.32 19.25 22.64705882 17.2 78.25 14.75 17.35294118 12.791.03 13.25 15.58823529 11.7 104.44 11.35 13.35294118 10.7

TABLE 3 Adsol Flush Rate 40 ml/min Initial Red Blood Cell SupplyHematocrit = 85.5 Time (s) HCT (%) HCT (%) Norm PLH (mg/dl) 0 83.597.66081871 426.1 13.98 83.25 97.36842105 402.4 22.89 54.5 63.74269006143 29.72 35.25 41.22807018 64.5 37.8 27 31.57894737 46.7 46.36 24.528.65497076 41.3 55.31 21 24.56140351 28.7 64.2 15.65 18.30409357 19.774.22 10.65 12.45614035 13.4 84.13 7.9 9.239766082 9.7 95.2 6.157.192982456 7.5

TABLE 4 Adsol Flush Rate 50 ml/min Initial Red Blood Cell SupplyHematocrit = 88.75 Time (s) HCT (%) HCT (%) Norm PLH (mg/dl) 0 88.2599.43661972 292.9 13.71 80.25 90.42253521 249.3 25.77 49 55.2112676190.9 33.32 32.75 36.90140845 49.6 36.25 28.25 31.83098592 24.7 43.7922.5 25.35211268 21 51.32 17.25 19.43661972 19.6 59.28 14.75 16.6197183114.9 67.11 11.9 13.4084507 12.6 75.44 8.1 9.126760563 7.8

TABLE 5 Adsol Flush Rate 60 ml/min Initial Red Blood Cell SupplyHematocrit = 86.5 Time (s) HCT (%) HCT (%) Norm PLH (mg/dl) 0 85.598.84393064 320.7 13.78 74.75 86.41618497 290.7 19.66 38.25 44.2196531856.8 23.84 31 35.83815029 40.7 29.74 28.5 32.94797688 37.9 36.88 24.7528.61271676 28.1 44.03 16.1 18.61271676 16.9 50.69 12.2 14.10404624 11.358.19 9 10.40462428 8.9 66.21 7 8.092485549 7.2

TABLE 6 Adsol Flush Rate 70 ml/min Initial Red Blood Cell SupplyHematocrit = 86.5 Time (s) HCT (%) HCT (%) Norm PLH (mg/dl) 0 87.5101.1560694 414.3 12.65 75.75 87.57225434 346.6 18.42 40.5 46.8208092580.2 23.03 25 28.9017341 60.7 28.98 21.5 24.85549133 47 36.41 21.224.50867052 39.3 42.7 15.8 18.26589595 25.1 50.5 11.65 13.46820809 18.358.31 7.75 8.959537572 12 65.83 5.9 6.820809249 9.7

TABLE 7 Adsol Flush Rate 80 ml/min Initial Red Blood Cell SupplyHematocrit = 88.75 Time (s) HCT (%) HCT (%) Norm PLH (mg/dl) 0 90101.4084507 692.8 11.21 71 80 399 16.18 36.5 41.12676056 116 21.19 2325.91549296 55.8 26.56 19.75 22.25352113 47.4 33.58 20 22.53521127 41.641.06 13.25 14.92957746 23.5 46.9 10 11.26760563 16.6 53.54 6.657.492957746 11.5 61.11 4.45 5.014084507 9.2 68.06 4.4 4.957746479 8.3

TABLE 8 Adsol Flush Rate 90 ml/min Initial Red Blood Cell SupplyHematocrit = 87.5 Time (s) HCT (%) HCT (%) Norm PLH (mg/dl) 0 87.2599.71428571 1224.6 9.53 80.5 92 1004.4 13.66 51.25 58.57142857 323.819.43 36 41.14285714 174.1 21.08 27 30.85714286 109.9 22.77 2326.28571429 75.2 26.9 22.5 25.71428571 79.5 30.77 20.75 23.71428571 69.234.95 18 20.57142857 54.1 35.4 15 17.14285714 45.9 44.93 12.7514.57142857 36

The hemolysis (PLH) vs. hematocrit (HCT) for each test was plotted asshown in the graph entitled PLH vs. HCT of FIG. 15E. The data of eachindividual test for a selected flush rate was then fitted to a best fitcurve. The equations of the best fit curve for each flush rate weredetermined and are listed below in Table 9. Given a desired amount ofhemolysis, the equations below can be used to calculate the hematocritthat the red blood cells in the filter must be at before a particularflush rate may be used.

TABLE 9 Flush Rate (ml/min) HCT vs. PLH 22 HCT = In(0.150*PLH)/0.0461 30HCT = In(0.131*PLH)/0.0428 40 HCT = In(0.111*PLH)/0.0482 50 HCT =In(0.071*PLH)/0.0433 60 HCT = In(0.138*PLH)/0.0483 70 HCT =In(0.081*PLH)/0.0435 80 HCT = In(0.089*PLH)/0.0504 90 HCT =In(0.131*PLH)/0.038

For example, using the above equation for a flush rate of 30 ml/min, ifthe desired hemolysis (PLH) is 50 mg/dl, the hematocrit should be 44% orless to use a flush rate of 30 ml/min and keep the blood product exitingthe filter within the desired amount of hemolysis of 50 mg/dl.HCT=ln(0.131*PLH)/0.0428  (1)HCT=ln(0.131*50)/0.0428  (2)HCT=44%  (3)

Next, the normalized hematocrit (HCT) vs. flush time for each test wasplotted, as shown in the Graph entitled HCT vs. Time-Flush (Normalizedto Inlet HCT) of FIG. 15F. The data of each test was then fitted to abest fit curve, the equations of which for each flush rate are listedbelow in Table 10. The equations below can be used to determine the timerequired to decrease the hematocrit of the red blood cells in the filterfor each flush rate.

TABLE 10 Flush Rate (ml/min) Time vs. HCT 22 Time = In(.0096*HCT)/−0.01730 Time = In(.0097*HCT)/−0.021 40 Time = In(.0089*HCT)/−0.029 50 Time =In(.0086*HCT)/−0.033 60 Time = In(.0092*HCT)/−0.040 70 Time =In(.0097*HCT)/−0.042 80 Time = In(.0105*HCT)/−0.046 90 Time =In(.0110*HCT)/−0.048

For example, when the flush rate is 30 ml/min, it will take about 11seconds for the red blood cells within the filter to decrease from ahematocrit of 50% to a hematocrit of 40%.Time_(d)=(ln(0.0097*HCT₁)/−0.021)−(ln(0.0097*HCT₂)/−0.021)  (1)Time_(d)=(ln(0.0097*50)/−0.021)−(ln(0.0097*40)/−0.021)  (2)Time_(d)=11 sec  (3)

Wherein:

HCT₁ is the initial hematocrit

HCT₂ is the second lower hematocrit

Time_(d) is the time it takes to decrease from HCT₁ to HCT₂

As described in more detail below and graphically shown in FIG. 15G, theabove correlations may be combined to determine the increases inadditive solution flush rate during filter flushing.

FIGS. 15H-15K graphically illustrate one example of how the correlationsmay be combined to produce an increasing flush rate during flushing. Inthis example the selected hemolysis is below about 50 mg/dl. Turningfirst to FIG. 15H, the graph shown therein is similar to that of FIG.15E except that lines have been added to indicate the intersection of 50mg/dl and 50% hematocrit. When filter flushing begins, the filter has ahigh hematocrit between, for example, 70% and 88%. As indicated by thegraph, the filter should be flushed with additive solution at 22 ml/minuntil the red blood cells within the filter have a hematocrit that isbelow 50%. If the flush rate is increased to higher than 22 ml/min witha greater than 50% hematocrit, according to this graph, hemolysis wouldundesirably increase and be much greater than 50 mg/dl.

Turning now to FIG. 15I, at a flush rate of 22 ml/min the graphindicates that it will take about 40 seconds for the hematocrit of thered blood cells within the filter to decrease from 88% to 50%.Accordingly, the initial flush rate of the additive solution in thisexample would be 22 ml/min for 40 seconds. After 40 seconds has passed,the additive solution flush rate is increased to 30 ml/min.

FIG. 15J is similar to FIG. 15H except that it includes lines showingthe intersection of 50 mg/dl and 40% hematocrit. As indicated by thisgraph, to keep the hemolysis at or below 50 mg/dl, the additive solutionflush rate should remain at 30 ml/min until the hematocrit of the redblood cells within the filter is at 40%. As graphically shown in FIG.15K, at an additive solution flush rate of 30 ml/min, it will take about12 seconds for the hematocrit of the red blood cells to decrease from50% to 40%. Therefore, the flush rate will remain at 30 ml/min for 12seconds. After 12 seconds have passed, the additive solution flush rateis increased to 40 ml/min until the hematocrit of the red blood cellswithin the filter is below 30%.

The above process is repeated to determine the rest of this increasingstep pattern until the flush rate reaches 90 ml/min and the flush rateremains at 90 ml/min until the flush is complete. The same or similarprocess for determining the ramping up of flush rates illustrated inthis example may be used to determine flush rates of different filters,additive solutions and/or blood products. Additionally, the variables(i.e. hemolysis, hematocrit and flow rates) also may be varied,depending on the application and desired outcome.

IV. Data Management Systems and Methods

The system described herein can also incorporate data managementsolutions. Weight scales and the addition label printing devices to thesystem would allow users to obtain product weight labels directly fromthe separation system at the completion of the procedure. Thiseliminates manual weighing and recording of data used in currentprocessing methods. The module B may include a suitable user interface,such as a touch screen, keypad or keyboard, as well as a scanner, toallow users to input information such as user donor identificationnumber, blood bank identification, fluid circuit kit numbers, lotnumbers, etc., which could also improve data management efficiency inblood manufacturing centers.

More specifically, and in accordance with another aspect of the presentdisclosure, a method is provided for automating the transfer of dataassociated with the whole blood collection container, as well as otherpertinent information, to the processing circuit used for the subsequentseparation of the whole blood and the final storage container orcontainers for such separated blood component or components. This methodis illustrated schematically in the flow chart of FIG. 29, where asource container is provided (step 122), which typically contains a unitof previously-collected whole blood, although the source container maycontain a previously-processed blood product. The source containertypically has data associated with it relating to the identification ofthe donor and the collection time, place, etc., such data preferablybeing in a machine-readable format, such as a bar code or a RFID tag.This data is then retrieved and transferred (step 124), and thenassociated with the processing circuit and final storage containers(step 126).

Turning to FIG. 30, one possible system for the use of a data managementsystem in accordance with the present disclosure is shown. A bloodcollection container 128 and a separate processing circuit 130 havingthree final storage containers 132, 134 and 136, are provided. Duringthe collection of the whole blood, donor identification information isencoded and associated with the container for the collected whole blood.This may be done by manually placing a bar code label for the donor idonto the container label, container pin, or tubing. It may also be doneby utilizing an RFID writer at the point of collection, transferring thedonor ID from a collection scale or hand-held device onto an RFID tagattached to the collection container. The use of RFID permits a greateramount of information to be managed, including such data ascontainer-type, expiration date, collection time, collection volume,nurse identification, collection site, and the like.

The automated data transfer between the collection container 128 and theprocessing kit 130/storage containers 132, 134, 136 may occur in thecontext of the sterile connection of the collection container 128 to theprocessing kit 130. For example, an electromechanical system thataccomplishes the sterile connection of the whole blood collectioncontainer to the processing kit may be used. Such a system is disclosedin U.S. Provisional Patent Application Ser. Nos. 61/578,690 and61/585,467 filed on Dec. 21, 2011 and Jan. 11, 2012, respectively, whichare incorporated herein by reference. The sterile connect device may befree standing, as shown in the above referenced provisionalapplications, or integrated with the reusable module B described above.Alternatively, the data management system may be simply associated withthe reusable module B, without a sterile connect device associatedtherewith. In any event, the sterile connection device or reusablemodule includes a programmable controller configured to automaticallyperform, or prompt the user to perform, the various steps of the datamanagement method, as described in greater detail below.

The data management system 138 incorporates a processing unit, a screen140 for providing information to the user (such as prompts andconfirmations), a touch pad 142 to permit the user to input information,and a scanner/reader 144 for retrieving and transferring informationbetween the collection container 128 and the processing kit 130. Thesystem 138 also provides for the printing of bar code labels or transferof data to one or more RFID tags associated with the processing kit.Turning now to FIG. 31, a flow chart generally illustrating the datamanagement method is shown. The method includes loading the collectionbag and processing kit onto the reusable module and/or sterile connectdevice (step 140). The data associated with the processing kit and thedata associated with the collection container is retrieved (steps 142and 144). As can be appreciated, the order in which these steps areperformed is not critical. As noted above, this data may take the formof a bar code, an RFID tag or other form, the processing kit and itsassociated collection containers have the pertinent data from thecollection container associated therewith. This may either take the formof printing bar code labels or writing data to an RFID tag (steps 146and 148). The collection container and processing kit are connected,preferably in a sterile connect procedure (step 150), such connectionoccurring at a time during the sequence of the performance of theabove-described steps.

The blood in the collection container is then processed (step 152). Theprocessing kit/storage container information is then retrieved andverified against the collection container data (steps 154 and 156).After such verification, the storage containers may be disconnected fromthe collection container (step 158).

The system of the present disclosure assists the user in performing thesteps described above in that it provides prompts and confirmations forthe various steps. For example, if the identifying information is in theform of a bar code, the system prompts the user to scan the bar code IDof the processing kit and the donor ID of the collection container. Thesystem will then print replicate bar code labels on a printer that iseither integral to the system or attached to it, with the type andquantity of the labels being determined by the type of processing kitloaded. The system then prompts the user to apply the bar code labels tothe final storage containers. After the system processes the blood intoits components, the system prompts the user to scan the final componentcontainer bar code IDs so that the system may verify correct bar codeinformation prior to detaching the storage containers from thecollection container and processing kit.

If the identifying information is associated with an RFID tag, thesystem automatically scans the RFID tag on the collection container andthen automatically reads the information on the RFID included on theprocessing kit. The system then automatically replicates the collectioncontainer information to the RFID tag or tags associated with theprocessing kit storage containers. After the system processes the bloodinto the components, according to the type of processing kit detected bythe instrument, the system will read the RFID tag on the final componentcontainers to permit verification of the identifying information priorto detaching the blood storage containers from the processing kit andcollection container.

It is contemplated that the system may employ both bar code and RFID asredundant systems, and include some or all of the steps described above,as applicable. While the bar code scanner/RFID reader is described asbeing associated with the reusable module B, it could be a dedicatedstation physically separate from the processing machine itself, thoughlinked through the data management software.

While this data management method has been described in connection withthe collection of the whole blood in a container separate from theprocessing kit and storage containers, it may equally well be used inconnection with a system or kit in which the collection container isintegral with the processing kit and its storage containers. Further,the method may be used in connection with the processing of whole blooddrawn directly from a donor, as described below, with the donoridentification data being provided by the donor, and not a collectioncontainer, or in a cell washing procedure, with the identification databeing associated with the source container.

V. Systems and Methods for Processing Whole Blood from a Donor

In accordance with another aspect of the present disclosure, thespinning membrane separator described above may be advantageously usedin the single step or “chairside” collection and separation of wholeblood into blood components. As described below, an automated wholeblood collection system is provided that separates whole blood into asingle unit of red blood cells and plasma simultaneously with thecollection of whole blood from a donor. The system is intended to be asingle pass collection system, without reinfusion back to the donor ofblood components. The system preferably comprises a disposable fluidflow circuit and a durable reusable controller that interfaces with thecircuit and controls fluid flow therethrough. The flow circuit ispreferably a single use pre-sterilized disposable fluid flow circuitthat preferably comprises red blood cell and plasma collectioncontainers, anti-coagulant and red cell additive solutions, a separatorand a fistula for providing a passageway for whole blood from the donorinto the fluid circuit. The durable controller preferably comprises amicroprocessor-controlled, electromechanical device with valving,pumping, and sensing mechanisms configured to control flow through thecircuit, as well as safety systems and alarm functions, appropriate fora whole blood collection procedure.

The method of blood collection utilizing the system comprises performinga venipuncture on a donor and the withdrawing whole blood from the donorinto the disposable circuit where it is manipulated by the instrumentand the components of the fluid circuit to result in the whole bloodbeing separated into the desired red blood cell and plasma components.The donor remains connected to the system throughout the procedure, andall fluids remain in the fluid path of the single-use kit until theprocedure is completed. As a “single pass” system, whole bloodpreferably passes through the flow circuit one time only, and no bloodcomponent is returned to the donor. In a further alternative, thecollection procedure is performed in two steps to permit the collectionof an increased volume of red blood cells from the donor. In a firststep, whole blood is withdrawn from a donor from which a first quantityof red blood cells and a first quantity of plasma are separated. At theend of the first step, the first quantity of separated plasma isreturned to the donor, after which collection and separation of wholeblood is resumed and a second quantity of red blood cells and a secondquantity of plasma are collected. The second quantity of separatedplasma is then returned to the donor.

The red blood cells resulting from the collection may not necessarily beprocess leukoreduced. However, leukoreduction by filtration may beachieved with a leukoreduction filter preferably integrated to thesingle use circuit or by the use of a separate processing circuit thatis sterile-connected to the red blood cell collection container.

The instrument preferably includes an operator interface for inputtinginformation and/or displaying information such as a touch screen,keypad, mouse, keyboard, etc. A message display allows the operator tocontrol the procedure, gather information on its status, and address anyerror conditions as they may arise.

Turning to the drawings, there is seen in FIGS. 16-19 a schematicrepresentation of a whole blood automated collection system, generallydesignated 210, in accordance with the present disclosure, in differentstages or phases of operation. The system preferably includes a reusablehardware component 212 that preferably comprises pumps, clamps andpressure sensors to control fluid flow, and a single-use pre-assembledsterile disposable fluid circuit component 214 that may be mountable tothe hardware component and includes various containers/pouches, a donoraccess device or fistula, and a blood separation chamber, allinterconnected by a sterile fluid pathway, such as flexible plastictubing. The containers/pouches are typically collapsible, and made of asuitable plastic material, as is well known in the art. The material ofthe containers may differ depending on usage, and may includeplasticizer-free materials such as DEHP-free polymers, particularly, butnot exclusively, for red cell storage.

More specifically, the illustrated fluid circuit component or module 214comprises a donor access device 216 that includes a first length oftubing 218 as the draw line through which whole blood is withdrawn froma donor and introduced into the fluid circuit 214. The donor accessdevice 216 preferably comprises a needle, and particularly a small gaugeneedle (18-21 gauge) for enhanced donor comfort with a needle guard ifdesired for prevention of inadvertent needle sticks. The tubing 218communicates with a blood separation device, generally designated 220and, as described above, to introduce whole blood into the separator.

A second length of tubing 222 provides for fluid communication betweenthe separator 220 and a first container/pouch 224 for receipt of theseparated concentrated red blood cells, while a third length of tubing226 provides for fluid communication between the separator 220 and asecond container/pouch 228 for the receipt of plasma.

The fluid circuit 214 also comprises a source of anticoagulant (e.g.,CPD), which is contained in a third container 230 that communicates withthe first length of tubing 218 by means of a fourth length of tubing 232that is joined to tubing 218 by, e.g., a Y-connector. The fluid circuit214 may also include a source of preservative solution for the red bloodcells that are to be delivered to the container/pouch 224. Thepreservative solution may be contained in a separate pouch that iscommunication with the container 224. Alternatively, the container 224may be pre-filled with an amount of preservative solution adequate forthe amount of red blood cells to be received therein during thecollection procedure.

The fluid circuit 214 also includes an integral sampling system 234 forthe aseptic collection of blood samples prior to and during the donationprocess. The sampling system 234 comprises a pouch that communicateswith the first length of tubing 218 of the donor access device through afifth length of tubing 236 upstream of the connection between tubing 218and tubing 232, through which the anticoagulant is introduced. Tubing236 preferably communicates with tubing 218 through a Y-connector orsimilar device.

Alternative disposable fluid circuits that may be used during anautomated whole blood separation procedure are seen in FIGS. 16A-16D.Each contains a core set of components which includes an invertedspinning membrane separation device 220 (with the inlet locatedproximate to the bottom of the separator and the outlets locatedproximate to the top), a plasma product container or bag 228, a redblood cell product container or bag 224, a whole blood collectioncontainer or bag 216 a connected to a donor access device 216 (such as aneedle), a red cell additive solution container or bag 230 a, a pressuretransducer connector 254 a, and a plurality of pump tubing keepers. Thewhole blood collection bag 216 a and additive solution bag 230 a may bepre-attached to the kit during manufacturing (as seen in FIGS. 16A-16C),or may be separate from the rest of the core components and attached tothe remainder of the fluid circuit at the time of the processing (asseen in FIG. 16D). (It is understood that any required anticoagulant hasbeen added to whole blood in the collection bag at or about the time itis withdrawn from the donor. Otherwise, the fluid circuits of FIGS.16A-16D may also incorporate a source of anticoagulant solution.)Additional components such as a leukofilter 236 (FIGS. 15B-15D), anadditive solution spike 264 (FIG. 16D), an additive solution filter 266(FIG. 16D), and sterile dock connectors 268 (FIG. 16D) can be added tothe core components.

FIGS. 16A and 16B depict fluid circuits compatible with the 2-pumpconfiguration of the automated separation device, such as thatillustrated in FIGS. 9 and 11-13, described above. FIGS. 16C and 16Ddepict fluid circuits compatible with the 3-pump configuration of theautomated separation device, with the fluid circuit of FIG. 16C havingthe whole blood collection bag 216 a and the additive solution bag 230 aintegrally attached, while whole blood collection bag 216 a and theadditive solution bag 230 a for the fluid circuit of FIG. 16D areseparate from the remainder of the fluid circuit and attached at thetime of processing.

More specifically, the fluid circuit of FIG. 16A is used in a 2-pumpdurable device configuration to produce a plasma product and anon-leukoreduced red blood cell product. The red cell additive solutionbag 230 a and whole blood collection bag 216 a are pre-attached to thefluid circuit. The fluid circuit of FIG. 16B is also used in a 2-pumpdevice configuration to produce a plasma product and a leukoreduced redblood cell product. As such, this fluid circuit contains a leukofilter262 integrated into the tubing 222 through which the separated red bloodcells flow. This allows the red blood cells to be leukoreducedimmediately upon exiting the spinner. The red cell additive solution bag230 a and the whole blood collection bag 216 a are pre-attached.

The fluid circuit of FIG. 16C is used in a 3-pump durable deviceconfiguration to produce a plasma product and a leukoreduced red bloodcell product. A second solution dilution line 232 b connects theadditive solution bag 230 a to tubing 222 for the separated red bloodcells. The line 232 a is passed through a pump (such as pump 240) tocontinuously pump additive solution into the separated red blood cellsafter exiting the spinning membrane 220 and prior to entering the filter262 to dilute the concentrated red blood cells. This decreases thehematocrit of the blood passing through the filter, thus improving redblood cell product quality. As with the embodiments of FIGS. 16A and16B, the red cell additive solution bag 230 a and the whole bloodcollection bag 216 a are pre-attached to the fluid circuit.

The fluid circuit of FIG. 16D is also configured to be used with a3-pump durable device configuration kit and includes means such as spike264 and sterile docks 268 for attaching the additive solution bag 230 aand whole blood collection bag 216 a to the circuit at the time ofprocessing. In this case, the fluid circuit must also include a sterilefilter 266 through which the additive solution is passed to ensuresterility. The sterile-connection may be made with current commonsterile connection devices (such as the Terumo® Sterile Tubing Welder)or with the sterile dock device 120 described above.

The means for attaching the various fluid containers at the point ofprocessing can be incorporated in any combination into the fluidcircuits of FIGS. 16A-16C. For example, the fluid circuit of FIG. 16Acan have both the additive solution bag 230 a and the whole blood bag216 a pre-attached (as shown), can have only the whole blood bag 216 apre-attached and the additive solution spike 264 for later attachment ofthe additive solution bag 230 a, can have only the additive solution bag230 a pre-attached and the sterile dock sites 268 for connecting thewhole blood collection bag 216 a, or can have neither the additivesolution bag 230 a nor the whole blood collection bag 216 a pre-attached(as shown in FIG. 16D).

Fluid circuits to which the whole blood collection bag 216 a ispre-attached are intended to be used at the point of collection. Incontrast, fluid circuits that include a sterile dock site for attachingthe whole blood collection bag 216 a will not travel to the point ofcollection, and only the separate whole blood collection bag 216 a willbe present at the point of collection. This may be beneficial to theuser, decreasing the amount of supplies that must travel to mobilecollection sites, as the fluid circuits that include a sterile dock sitefor attaching the whole blood collection bag 216 a do not need to travelto the point of collection.

The durable hardware component 212 preferably comprises a first pump 238that cooperates with tubing 218 for pumping whole blood to theseparation device 220 and a second pump 240 that cooperates with thetubing 222 for transporting substantially concentrated red blood cellsfrom the separation chamber 220 to the first collection container 224.The pumps 238, 240 are preferably peristaltic or roller pumps thatinclude a rotor with one or more rollers for compressing the tubing toforce the fluid to be moved therethrough, although other suitable pumpdesigns, such as flexible diaphragm pumps, may also be used. Thehardware component also preferably includes a third pump 242 thatcooperates with tubing 232 for transporting anticoagulant to the drawline tubing 218 through which whole blood is transported to theseparator 220. The third pump 242 provides for metering the flow ofanticoagulant, and also facilitates the priming and rinsing of thesystem, as will be described below. However, the third pump 242 isoptional, and anticoagulant may be metered to the whole blood draw line218 by gravity flow, with the tubing 232 being dimensioned to provide asuitable flow rate over the duration of the collection procedure.

The hardware component 212 also preferably comprises clamps 244, 246,248 and 250 for selectively occluding and opening the tubing segments218, 232, 222, and 226, respectively. The term “clamps” is used broadlyherein, and includes any mechanism that cooperates with the flow paths,e.g., tubing segments, of the fluid circuit to selectively permit orpreclude fluid flow therethrough. The hardware component 212 alsopreferably comprises pressure sensors 252, 254 in the draw line tubing218 proximate or adjacent the needle (pressure sensor 252) and proximateor adjacent the inlet to the separator 220 (pressure sensor 254) tomonitor the inlet pressure, such as to detect a vein collapse. A weighscale (not shown) is also preferably provided for at least the firstcontainer 224 to provide feedback on the red blood cell volumecollected.

In keeping with another aspect of the disclosure, the reusable hardwarecomponent preferably comprises a programmable controller 256 foractuating the pumps and clamps and monitoring the pressure sensors andweigh scales so that the whole blood collection procedure may besubstantially automated. The controller 256 comprises a programmablemicroprocessor, and preferably includes an operator interface, such astouch screen and message display to allow the operator to enter and viewdata and control the procedure, gather information on its status, andaddress any “error” conditions that may arise.

To perform an automated collection and separation procedure with theautomated blood collection system 210 thus far disclosed, the disposablefluid circuit 214 is loaded into operating position on the reusablehardware component 212 as shown in FIG. 16 of the accompanying drawings.In the phase or stage shown in FIG. 16, the system is primed with fluidto substantially remove air and wet the filter membrane. In the primarystage, the first clamp 244 is closed so as to prevent fluidcommunication between the donor access device 216 and the bloodseparation chamber 220, and anticoagulant is pumped via pumps 240 and242 through the tubing 218, separator 212, and tubing 222 to prime thesystem. A venipuncture is then performed on the donor with the needle ofthe donor access device to admit whole blood into the tubing 218. Atthis point, the whole blood may be sampled by means of the samplingpouch 234.

Turning to FIG. 17, after priming, the first clamp 244 is opened to flowwhole blood through the tubing 218 to the blood separator 220, via pump238, to commence the collection/separation phase of the collectionprocedure. The anticoagulant continues to be metered into the draw linetubing segment 218 through tubing segment 232 by means of the third pump242. Red blood cells exit the separator 220 through tubing 222. Thefourth clamp 250 is opened so as to permit plasma to exit the separator220 and to travel through the tube 226 to the second collectioncontainer 228. The first pump 238 presents the whole blood flow to theseparator 220, with the inlet pressure being monitored by sensor 254,while the red blood cells are pumped from the separation chamber 220 bythe second pump 240. The flow differential between the first pump 238and the second pump 240 forces the separated plasma to exit theseparator 220 into the second collection container 228.

With reference to FIG. 18, when the volume of the red blood cells in thefirst collection container 224 reaches a predetermined volume (asmeasured by the weight of the first collection container 224 as detectedby the weigh scale), the weigh scale will provide the controller 256with a signal that prompts the controller to terminate the collectionprocedure by closing the first clamp 244, thus occluding the draw line218. The donor access device 216 may be withdrawn from the donor at thistime. If the system is to be rinsed, the fourth clamp 250 is closed toocclude the flow line 226 to the second collection container 228 for theplasma. The first pump 238 is deactivated while the third pump 242continues to deliver anticoagulant to the separator 220 with theanticoagulant being exhausted to the first collection container 224through the tubing segment 222.

Turning to FIG. 19, at the conclusion of the rinse cycle, the secondclamp 246 and third clamp 248 are closed, and the second pump 240 andthird pump 242 deactivated.

At this point, the first collection container 224 containing thesubstantially concentrated red blood cells may be separated from thedisposable fluid circuit 214 for storage or to facilitateleukofiltration. This may be done by simply hanging the collectioncontainer 224 and allowing gravity filtration of the red blood cellsthrough a leukoreduction filter into a final storage container. However,in accordance with another aspect of the disclosure, and as shown inFIG. 20, a third collection container 258 may be provided that is influid communication with the second collection container 224 through atubing segment 260, with the tubing segment 260 being in fluidcommunication with tubing segment 222 through a Y connector located ontubing segment 222 between the outlet of the separator 220 and thesecond pump 240. The third clamp 248 may then be opened to permit theflow of concentrated red blood cells out of the collection container224, with the second pump 240 activated and pumping in the reversedirection to force the flow of concentrated red blood cells through theleukocyte reduction filter 262 and into the collection container 258.The pressure generated by pump 240 expedites the filtration processsignificantly as compared to gravity-fed leukofiltration of red cells.

As a further alternative, leukoreduction may be performed with respectto the whole blood during the draw phase of the operation. Turning toFIGS. 21 and 22, the draw line tubing 218 may include a leukocytereduction filter 264 that is in line with the tubing 218. The filter 264is located upstream of the first pump 238 so that the pump will exert asufficient draw force on the blood to draw it through the filter 264during collection. The leukofilter 264 may be located on the tubingsegment 218 either upstream of where the anticoagulant is introducedinto the system (as shown in FIG. 21) or downstream of where theanticoagulant is introduced into the draw line 218 (as shown in FIG.22). Placement downstream of the anticoagulant junction allows the useof anticoagulant to flush any remaining whole blood from the filter 264after the draw from the donor is completed. Also, placement of aleukoreduction filter in the draw line tubing 218 eliminates the needfor a separate downstream leukoreduction filtration step, thus furtherstreamlining the blood collection process.

The collection and separation method discussed above is a “single-pass”method, i.e., whole blood is withdrawn from the donor, and no separatedblood components or other replacement fluid is returned. In keeping withanother aspect of the disclosure, a method of simultaneously collectingwhole blood from a donor and separating out the red blood cells using aspinning membrane separator is provided in which at least a portion ofseparated plasma is returned to the donor so that an increased quantityof red blood cells may be harvested from the donor.

Specifically, the illustrated system and method utilize an inventedspinning membrane separator as described above to produce up to twoleukoreduced red blood cell products during an apheresis procedure. Aschematic of one potential system layout is shown in FIG. 22A (in whichprimarily the durable hardware components are identified) and FIG. 22B(in which the disposable flow circuit components are identified). FIG.22L depicts the disposable flow circuit or kit separately from thedurable hardware component. FIGS. 22C-22H depict the cycles and flowpaths of a double collection procedure utilizing the flow circuitillustrated in FIG. 22L. These figures represent one of many potentiallayouts, and various other component configurations are possible, aswould be apparent to one skilled in the art.

As illustrated in FIGS. 22A-22I, the system comprises four pumps (inletpump 238, outlet pump 240, additive solution pump 242, andsaline/anticoagulant pump 242 a), four clamps (donor clamp 244,anticoagulant clamp 246 a, saline clamp 246 b, and plasma clamp 250),three pressure sensors (donor pressure sensor 252, spinner pressuresensor 254 and filter pressure sensor 262 a—the donor and spinnerpressure sensors are generally considered to be required, while thefilter pressure sensor is optional if filter clogging/plugging detectionis desired), a leukofilter 262, and a spinning membrane separator 220.As illustrated, the spinning membrane separator 220 is in the “upsidedown” configuration, with the whole blood inlet located at the lower endof the separator and the plasma and red blood cell outlets located atthe upper end, as described above. The system also optionally includes ahematocrit sensor 264, in the event that the operator is not able toinput into the controller the donor hematocrit. Otherwise, a hematocritsensor is not required.

The double red blood cell collection procedure includes a priming cycleand a first draw/separation cycle, generally as described above inconnection with FIGS. 16-22. However, after the draw/separation cycle,the separated plasma is returned to the donor, and a seconddraw/separation cycle is performed, after which the separated plasma isagain returned to the donor.

Referring to FIG. 22C, the priming cycle is illustrated by which air isremoved from the tubing of the kit and the membrane of the separator iswetted. Red blood cell additive solution is pumped out of the solutionbag 230 a and into the solution line 232 a through the leukofilter 262and into the red blood cell lines 222 a by pump 242 (with the directionof rotation of the pump being indicated by the arrow associatedtherewith). Anticoagulant is pumped out of the anticoagulant bag 230into the anticoagulant line 232 and saline is pumped out of the salinebag 230 b into the saline line 232 b by the pump 242 a, with thesaline/anticoagulant then being pumped through the saline/anticoagulantline 232 c, the donor line 218, the inlet line 218 a, the spinningmembrane 220, the plasma line 226, and the outlet line 222 by means ofpumps 238 and 240. Saline, rather than anticoagulant, is preferred forpriming of the spinning membrane separator 220. If anticoagulant is usedto prime the spinning membrane separator membrane, the citrate infusionrate during the first return to the donor of separated plasma would behigher than desirable.

After the priming cycle is completed, the first draw and separationcycle is performed, during which whole blood is drawn from the donor andseparated into plasma and a leukoreduced red blood cell product. Thiscycle generates the first two red blood cell products that are to becollected. (If only a single red blood cell product is desired, theprocedure is complete after this draw and separation cycle.)

Referring to FIG. 22D, whole blood is drawn out of the donor and pumpedinto the spinning membrane device 220 by the inlet pump 238. The wholeblood is separated into plasma and packed red blood cells (typicallyhaving a hematocrit of greater than 80%) by the spinning membrane 220.The red blood cells are passed through the leukofilter 262 as they exitthe spinner 220 prior to entering the red blood cell product bags 224.The kit is configured to allow even distribution of the red blood cellsinto the two product bags 224. Leukoreduction during separation ispreferred. However, the separated red blood cells could be floweddirectly from the spinning membrane separator 220 into the product bags224, and then leukofiltered at a later time after the donor isdisconnected. During draw/separation cycle, the additive solution pump242 is continuously pumping additive solution into the packed red bloodcells as they exit the spinner 220 prior to entering the leukofilter262. Adding additive solution to the packed red blood cells decreasesthe hematocrit of the blood within the filter, which decreases thepossibility of hemolysis and microparticle generation within the filter262. The saline/anticoagulant pump 242 a is continuously pumpinganticoagulant into the whole blood as it exits the donor to preventclotting of the blood. This flow pattern is continued until a first redblood cell product has been collected.

The spinner pressure sensor 262 monitors the trans-membrane pressure ofthe spinning membrane 220 and controls plasma flow through the membranepreferably according to the control algorithm disclosed in U.S. patentapplication Ser. No. 13/095,633, incorporated by reference above. Thedonor pressure sensor 252 monitors the vein pressure of the donor todetect vein occlusions. The filter pressure sensor 262 a monitors thepressure across the leukofilter 262 to detect filter occlusions.

After the first draw/separation cycle is completed, a first plasmareturn cycle is performed, during which the plasma collected during thefirst draw/separation cycle is flowed back to the donor. (If only asingle red blood cell product is desired, the separated plasma can bekept as a product, instead of being returned to the donor, as is thecase in the procedures illustrated in FIGS. 16-22.)

Turning to FIG. 22E, plasma is pulled out of the plasma bag 228 by theinlet pump 238. Plasma then flows back across the membrane in theseparator 220 (reverse of the normal direction) through the inlet line218 a, the donor line 218, and back into the donor. The donor pressuresensor 252 monitors the donor's vein pressure. The plasma is returned tothe donor until the plasma bag 228 is emptied. Once the first quantityof separated plasma is returned, the first cycle is complete, with onered blood cell product having been collected.

Upon completion of the first cycle, a second cycle is commenced thatincludes the draw/separation and plasma return steps substantially asdiscussed above with reference to FIGS. 22D and 22E to collect thesecond of the two red blood cell products. The second draw/separationstep is shown in FIG. 22F, with the red blood cell collection bags 224being filled upon completion, and the flow paths are the same asdescribed in connection with FIG. 22E. A second plasma return cycle isperformed to return the plasma collected during the seconddraw/separation cycle back to donor, as shown in FIG. 22G, with the flowpaths being the same as described in connection with FIG. 22E.

After the second quantity of plasma is returned to the donor, saline maybe flowed to the donor. After the total desired volume of red bloodcells is collected, the leukofilter 262 may be flushed withstorage/additive solution to recover red blood cells and increaseproduct volume to meet requirements.

With reference to FIG. 22H, the saline return and filter flush can occursimultaneously. Saline is pumped out of the saline bag 230 b by thesaline/anticoagulant pump 242 a directly into the donor. Saline can alsobe used to rinse residual plasma out of the spinning membrane 220, theinlet line 218 a, and the donor line 218 if it is necessary to recoverthis plasma. Additive solution is pumped out of the solution bag 230 aby the solution pump 242 through the leukofilter 262 and into the redblood cell product bags 224. Once these steps are completed theprocedure is complete.

As described above, the return flow path for the plasma passes throughthe membrane of the separator 220 as it is returned to the donor. Thisis the preferred route as it is the most direct. However, a separateplasma return flow path may be provided that bypasses the separator, asshown in FIGS. 22I and 22K. This requires a line 266 that bypasses thespinning membrane separator and an additional plasma clamp 250 a.

The procedure for the collection of a double red blood cell productdescribed above is a batch process in which the whole blood is separatedand components collected only during the draw cycles. Unwantedcomponents, such as plasma, are returned to the donor during returncycles, during which separation of blood is postponed. Continuous batchprocessing, in which whole blood is continuously separated during boththe draw and return cycles, is preferable, as the return rate ofseparated plasma, which varies from donor to donor, will not affectprocedure times. Further, slower separation rates may be used, whichimproves separation efficiency.

With reference to FIGS. 22J, 22K, and 22N, continuous batch processingmay be accomplished by adding to the disposable fluid circuit describedin connection with FIGS. 22A and 22B an in-process reservoir 268upstream of the separator 220 and a separate plasma return line 266 aconnecting the plasma bag 228 to the donor line 216, and adding to thehardware device an additional inlet pump 238 a that engages the donorline upstream of the in-process reservoir 268. Other aspects of thehardware device and processing kit of FIGS. 22A and 22B are unchanged.

With reference to FIG. 22J, the draw cycle of a continuous batch processis shown. In general, whole blood is withdrawn from the donor throughthe donor line 216 by the draw/return pump 238 a and then flowed intothe in-process reservoir or bag 268. Whole blood is then pumped from thein-process bag 268 by the inlet pump 238 and into the spinning membraneseparator 220, where plasma is separated from the cellular componentsand flowed through tubing 226 into the plasma bag 228.

Preferably, the draw/return pump 238 a draws whole blood from the donorinto the in-process bag 268 at a flow rate greater than the flow rate atwhich the inlet pump 238 flows whole blood out of the in-process bag 268and into the spinning membrane separator 220. The difference between therate of the draw/return pump 238 a and the rate of the inlet pump 238 isthe rate at which the in-process bag 268 will fill with whole bloodduring the draw cycle. Preferably, the in-process bag 268 is filled withwhole blood during the initial draw cycle to have whole blood availablefor separation during the subsequent return cycle, described below. Thedraw cycle preferably continues until the plasma bag 228 issubstantially filled.

With reference to FIG. 22K, the return cycle is shown. During the returncycle, whole blood continues to be pumped from the in-process bag 268into the spinning membrane separator by the inlet pump 238, and theplasma that is separated from the cellular components is flowed into theplasma bag 228 through tubing 226. Simultaneously, plasma collectedduring the previous draw cycle is flowed out of the plasma bag 228through the plasma return line by the draw/return pump 238 a andreturned to the donor.

Preferably, the rate at which plasma is returned to the donor is greaterthan the rate at which plasma is being separated from the cellularcomponents by the spinning membrane separator 220, thus allowing theplasma bag 228 to empty. Whole blood continues to be separated andplasma returned to the donor until the plasma bag 228 empties. If thein-process bag 268 empties before the plasma bag 228 empties, separationstops until the commencement of the next draw cycle. The draw/returncycles will continue until the desired amount of red blood cells hasbeen collected.

As described above, the return flow path for the plasma passes throughthe membrane of the separator 220 as it is returned to the donor. Thisis the preferred route as it is the most direct. However, a separateplasma return flow path may be provided that bypasses the separator, asshown in FIGS. 22I and 22M. This requires a line 266 that bypasses thespinning membrane separator and an additional plasma clamp 250 a.

The automated whole blood collection system and method described hereinare expected to improve blood collection center efficiency, and decreasethe operational costs, by accomplishing the separation of whole bloodinto red blood cell and plasma components without the need forsubsequent manual operations. Further, the use of smaller-gauge needlesin the donor access devices used with the system should enhance donorcomfort, while the use of a draw pump allows the system to achievedonation times similar to typical whole blood collection. Additionally,by having the whole blood collection controlled by microprocessor,greater opportunities for data management are provided that are nottypically found in current manual whole blood collection methods,including the use of integrated bar code readers and/or RFID technology,as described above.

In accordance with another aspect of the disclosure, methods, systems,and devices useful in the washing of biological cells, such as bloodcells or other blood or biological components, are described below.

VI. Systems and Methods for Cell Washing

Biological cell washing may serve several purposes. For example, cellwashing may be used to replace the liquid medium in which biologicalcells are suspended. In this case, a second liquid medium is added toreplace and/or dilute the original liquid medium. Portions of theoriginal liquid medium and the replacement liquid medium are separatedfrom the cells. Additional replacement liquid media may be added untilthe concentration of the original liquid medium is below a certainpercentage. Thereafter, the cells may be suspended in, for example, thereplacement medium.

Cell washing may also be used to concentrate or further concentratecells in a liquid medium. The cells suspended in a liquid medium arewashed, such that a portion of the liquid medium is separated andremoved from the cells.

Furthermore, cell washing may be used to remove undesired particulates,such as gross particulates or unwanted cellular material from a cellsuspension of a particular size or “purify” a desired cell suspension orother liquid.

The method, systems, and apparatus described below may be employed towash cells for any of the above-described reasons. More particularly,but without limitation, the methods, systems and apparatus describedbelow may be used to wash blood cells such as red blood cells or whiteblood cells (leukocytes), or platelets.

In one particular embodiment, a suspension including white blood cellsin a liquid culture medium may be washed to replace the liquid culturemedium with another medium, such as saline, prior to use or furtherprocessing. The cell suspension including white blood cells in a liquidculture medium is delivered and introduced into a separator, such as aspinning membrane separator. The spinning membrane separator has amembrane filter with a pore size smaller than the white blood cells. Inone embodiment, a liquid wash medium including the replacement liquidmedium, such as saline, is also added to the separator to dilute theliquid culture medium. The separator is operated such that the liquidspass through the pores of the membrane and are extracted as waste. Inthis embodiment, as the liquid is extracted, the wash medium is added,such that the resulting cell suspension includes white blood cellssuspended in the replacement liquid medium (e.g., the saline).

In another embodiment, the cell suspension may be concentrated (byremoving supernatant) and collecting the concentrated cell suspension ina container of the processing set. Replacement fluid may be introducedinto the separator, combined with the concentrated cells in thecontainer and the cells then resuspended with the replacement fluid. Ifnecessary, the resuspended cells/replacement fluid may be introducedinto the separator to further concentrate the cells, remove supernatant,and resuspend the concentrated cells with additional replacement fluid.This cycle may be repeated, as necessary.

Similar processes may be used to wash red blood cells suspended in aliquid storage medium. The cell suspension including red blood cellssuspended in a liquid storage medium may be washed to replace the liquidstorage medium with another medium, such as saline, prior to use orfurther processing. The cell suspension is delivered and introduced intoa separator, such as a spinning membrane separator. The spinningmembrane separator has a membrane filter with a pore size smaller thanthe red blood cells. In one embodiment, a wash medium, i.e., replacementliquid medium, such as saline, may also be added to the separator todilute the liquid storage medium. The separator is operated such thatthe liquid passes through the pores of the membrane and is extracted aswaste. As the liquid is extracted, the wash medium is added, such thatthe resulting cell suspension includes red blood cells suspended in thereplacement liquid medium (i.e., the saline). The wash and/orreplacement liquid may also be a storage medium that includes nutrientsand other components that allow for the long-term storage of the cells.Alternatively, in another embodiment, the red blood cells may first beconcentrated and removed to a container, as generally described above.Replacement fluid may then be combined with the red blood cells in thecontainer. The replacement fluid may be directly introduced into thecontainer, or introduced into and through the separator and then intothe container.

The systems, methods, and apparatus for cell washing described hereinutilize a disposable set that includes a separator, such as a spinningmembrane separator. The disposable set with the spinning membraneseparator is mounted onto the hardware component of the system, i.e.,separation device. The separation device includes clamps, pumps, motors,air detecting sensors, pressure transducer sensors, Hb detectors, weightscales, and a control logic/microprocessor included in a microprocessor.The control logic/microprocessor receives input data and signals fromthe operator and/or the various sensors, and controls the operation ofthe clamps, pumps and motors.

The cell suspension to be washed, i.e., cells suspended in a medium, maybe provided in a sterile, disposable source container, which isconnected, in sterile fashion, to the disposable set. A wash medium,such as saline or other suitable liquid, is also connected in sterilefashion or pre-attached to the disposable set. The control logic of thedevice operates the clamps and pumps to circulate the cell suspensionthrough the tubing of the disposable set to the (spinning membrane)separator. The separation device, through its control system, alsodirects the wash solution through the tubing of the disposable set tothe spinning membrane separator. The cell suspension and the washsolution may be mixed within the spinning membrane separator, may bemixed prior to entering the spinning membrane separator, or may becombined in a container after the cell suspension has been concentrated.Within the spinning membrane separator, the suspension medium isseparated from the cells suspended therein. The suspension medium andremaining wash medium (if the suspension medium and wash medium havebeen combined) exits through a waste port, while the cells pass througha separate exit port.

If further washing and dilution is necessary, the washed cells may bere-circulated through the separator with an additional volume of thewash solution. In one embodiment, the cells that are to be “re-washed”may be transferred to one or more in-process containers, as will bedescribed below. The control logic of the device operates clamps andpumps to circulate the cell suspension from the in-process containerthrough tubing to an inlet of the spinning membrane separator or to aninlet of a second spinning membrane separator. Further wash medium isadded, and the process repeats until an acceptable amount orconcentration of the cells is achieved. The final cell suspensioncontaining the cells is preferably collected in a final productcontainer.

In accordance with the present disclosure, FIGS. 23-25 show exemplarysystems useful in the washing of biological cells, such as, but notlimited to, red blood cells and white blood cells. As noted above, thespecific embodiments disclosed are intended to be exemplary andnon-limiting. Thus, in one embodiment, the system described hereinincludes a disposable set 300 (FIG. 23 or 24) and hardware component ordevice 400 (FIG. 25). It will be appreciated that the disposableprocessing sets 300 shown in both FIGS. 23 and 24 are, in many respects,identical and common reference numerals are used in both FIGS. 23 and 24to identify identical or similar elements of the disposable processingsets. To the extent that disposable processing sets differ in structureor in their use, such differences are discussed below. Disposable set300 is mounted onto device 400 (FIG. 25), which is described in greaterdetail below.

As shown in FIGS. 23-24, separator 301 is integrated into the exemplarydisposable set 300. Additionally, as will be described in greater detailbelow, disposable set 300 includes tubing, Y-connectors, in-processbag(s), sample pouch(es), final product bag(s), waste bag(s), andsterile filter(s).

The cell suspension to be washed is typically provided in a sourcecontainer 302, shown in FIGS. 23 and 24 as disconnected from thedisposable set. As noted above, source container 302 may be attached (insterile fashion) at the time of use. Source container 302 has one ormore receiving ports 303, 305, one of which may be adapted to receivespike connector 304 (FIG. 23) of disposable set 300. More particularly,source container 302 is connected to the disposable set 300 via thespike connector 304, which is connectable to access port 303. Morepreferably, however, source containers (and the fluid therein) may befree of a spike connector (as shown in FIG. 24) and accessed in asterile manner by employing sterile docking devices, such as theBioWelder, available from Sartorius AG, or the SCD IIB Tubing Welder,available from Terumo Medical Corporation. A second access port 305 mayalso be provided for extracting fluid from the source bag 302.

As further shown in FIGS. 23-24, tubing segment 306 may optionallyinclude a sampling sub-unit at branched-connector 308. One branch ofbranched-connector 308 may include a flow path 310 leading to samplepouch or site 312. Sample pouch or site 312 allows for the collection ofa sample of the incoming source fluid. Flow to the sample pouch or site312 is typically controlled by clamp 314. The other branch ofbranched-connector 308 is connected to tubing 316. Tubing 316 isconnected to further downstream branched-connector 318.Branched-connector 318 communicates with tubing 316 and tubing 320,which provides a fluid flow path from in-process bag 322, described ingreater detail below. Tubing segment 324 extends from one of the portsof branched-connector 318 and is joined to a port of further downstreambranched-connector 326. A separate flow path defined by tubing 328 isalso connected to a port of branched-connector 326. Tubing 328 mayinclude an in-line sterile barrier filter 330 for filtering anyparticulate from a fluid before it enters the flow path leading tosecond branched-connector 326 and, ultimately separator 301.

In accordance with the system disclosed herein, a wash solution may beattached (or pre-attached) to set 300. As shown in FIGS. 23 and 24,tubing 332 (defining a flow path) preferably includes spike connector334 at its end. Spike connector 334 is provided to establish flowcommunication with a container of a wash fluid, such as a disposable bagcontaining saline or other solution (not shown). The wash medium orfluid flows from the wash fluid source, through the second spikeconnector 334, through tubing segment 332, where it is filtered by thesterile barrier filter 330 described above, and then passes throughtubing 328 to the input of the branched-connector 326 described above.

Tubing segment 336 defines a flow path connected at one end to a port ofbranched-connector 326 and to an inlet port of the separator 301.Preferably, in accordance with the present disclosure, separator 301 isa spinning membrane separator of the type described above.

As shown in FIGS. 23, 24 and 25, the spinning membrane separator 301 hasat least two outlet ports. Outlet 646 of separator 301 receives thewaste from the wash (i.e., the diluted suspension medium) and isconnected to tubing 338, which defines a flow path to waste productcontainer 340. The waste product container includes a further connectionport 341 for sampling or withdrawing the waste from within the productcontainer.

Separator 301 preferably includes a second outlet 648 that is connectedto tubing segment 342. The other end of tubing segment 342 is connectedto branched-connector 344, which branches into and defines a flow pathto one or more in-process containers 322 and a flow path to a finalproduct container 350. The final product container 350 may also includea sample pouch 352 (see FIG. 23) and an access port or luer connector354. Sample pouch 352, shown with a pre-attached tube holder 352 in FIG.23, allows for sample collection of the final product. Flow control tothe sample pouch 352 is preferably controlled by clamp 356. The flowpath through the access port 354 is controlled by clamp 358.

Turning now to the method of washing using the kit 300 of FIGS. 23 and24, the disposable set 300 is first mounted onto panel 401 of theseparation device (i.e., hardware) 400, shown in FIG. 25. Device 400includes peristaltic pumps, clamps, and sensors, which control the flowthrough the disposable set. More specifically, control of the pumps,clamps and the like is provided by a software-drivenmicroprocessor/controller of device 400. Tubing segments 362, 366 and368 (shown in FIG. 23) are selectively mated with peristaltic pumps 402,404, or 406 (shown in FIG. 25). (Waste line pump segment 368 may berelocated to separator outlet line 342, if desired.) Once the disposableset 300 is mounted onto the control panel 401 of device 400, the cellsuspension in product bag 302 is attached, as previously described, byspike connector 304 or by sterile connection. A wash medium provided ina container (not shown) is likewise attached. In accordance with theoperation of device 400, clamp 360 is opened and allows the cellsuspension to flow from the product container 302.

Flow of the cell suspension is advanced by the action of peristalticpump through the tubing 324 designated by the pump segment 362 and intothe spinning membrane separator 301. Similarly, wash medium is advancedby the action of peristaltic pumps through the length of tubing 328designated by the pump segment 366 with valves 362 and 364 in an openposition. The wash medium flows through tubing 332, the sterile barrierfilter 330, tubing 328, Y-connector 326, and into the spinning membraneseparator 301. The wash medium and the cell suspension may besequentially introduced into spinning membrane separator 301, allowingfor mixing of the suspension and wash solution to occur within thechamber (gap) of separator 301 or in in-process container 322, asdescribed below. Alternatively, the wash medium and cell suspension maybe combined prior to introduction into separator 301 at (for example)the second branched-connector 326.

In yet a further alternative, cell suspension may first be introducedfrom source container 302 into separator 301, as generally describedabove. Cell suspension is concentrated within separator 301, allowingsupernatant to pass through membrane, through outlet port 382, to wasteproduct container 340. Concentrated cells exit separator 301 throughport 384 and are directed to in-process container 322.

Once separation of concentrated cells from supernatant of the cellsuspension is completed, replacement fluid is introduced from areplacement fluid container (not shown) into separator 301 (to flush outany residual cells) and is likewise directed through port 384 toin-process container 322. The concentrated cells are resuspended in thereplacement fluid within in-process container 322, as shown in FIG. 23.If additional washing is desired or required, the system may bepre-programmed or otherwise controlled to (re)introduce the resuspendedcells/replacement fluid into separator 301, wherein the separation ofconcentrated cells from supernatant is repeated. The final cell productis collected in final product container 350, where it may be resuspendedwith additional replacement fluid.

Regardless of the sequence of cell suspension/wash solution introductionor the disposable set used, the spinning action of the device causescells to separate from the remainder of the fluid in which it wassuspended and/or from the wash solution. Preferably, the supernatant andthe wash solution pass through the membrane while the desired cells areconcentrated within the chamber of the separator. The waste resultingfrom the separation, which includes wash medium and supernatant medium,exits port 382 and flows through tubing 338 to waste product container340. The flow of waste is controlled by peristaltic pump through aportion of tubing 338 designated by the pump segment 368 to the wasteproduct bag 340.

As described above, the concentrated and separated cell suspension exitsthe second outlet 384 of the spinning membrane separator 301. If nofurther washing is required, the control system closes clamp 370 andopens clamp 372. The closing of clamp 370 prevents the washed cellsuspension from flowing through the tubing 346 and directs it throughtubing 348 to the final product bag 350. The final product container 350has an input for receiving the separated and washed cell suspension. Thefinal product container 354 is connected to a weight sensor 374. Theseparation device measures the weight 374 of the container to determinewhether the volume of the collected cells in final product container 350is in the acceptable range and, therefore, whether the washing cycle iscomplete.

If further washing of the separated cell suspension is desired orrequired, the control system of separation device closes clamp 372 andclamp 376 and opens clamp 370. The closing of clamp 372 prevents thecell suspension from flowing through the tubing 348 and directs itthrough tubing 346 to the in-process bag 322. The in-process bag 322 hasan inlet for receiving the separated cell suspension. The in-process bag322 is connected to a weight sensor 378. The control system of theseparation device determines the weight as sensed by weight sensor todetermine whether enough of separated cell suspension is present in thein-process bag 322 to conduct another wash cycle. If it is determinedthat enough of the suspension is present, and further washing isdesired, the control system of the separator device opens clamp 376 toopen and directs the diluted and separated cell suspension through theoutput of the in-process bag 322, through tubing 320, intobranched-connector 318, and through an air detector sensor 380. The airdetector sensor 380 detects air in the cell suspension which passesthrough tubing 324. The control and operation device measures thereadings from air detector sensor 380 and determines the furtherprocesses to be taken.

The separated cell suspension which includes cells suspended in dilutedsuspension medium is then passed through the washing process again, asdescribed above. The wash process may be repeated as many times asdesired and preferably until the diluted and separated cell suspensionhas an acceptable remaining concentration of suspension medium. Thefinal diluted and separated cell suspension is collected in the finalproduct bag 350.

Alternatively, rather than repeatedly processing the fluid through asingle in-process container, a “batch-type” processing procedure may befollowed by using two or more in-process containers 322 (in combinationwith final product container 350).

The disposable processing set 300 of FIG. 24 is particularly well suitedfor such “batch-type” processing. In accordance with a cell washingprocedure using disposable set 300 of FIG. 24, cells initially separatedfrom the original suspension medium are removed from separator 301 andintroduced into one of the in-process containers 322 a. Replacementfluid is introduced into container 322 a and the cells resuspended.Resuspended cells in container 322 a may then be introduced intoseparator 301 wherein they are separated from the supernatant.Concentrated cells exit through outlet 648 in separator 301 and areintroduced into a fresh (second) in-process container 322 b. Additionalreplacement fluid may be introduced into in-process container 322 b, andthe process repeated, if necessary, with a further fresh (third)in-process container (not shown). The final cell product is thencollected in final product container 350, as described above.

In accordance with the “batch-type” cell washing method described above,tubing segments 370 a, 370 b and 320 a, 320 b may be associated withclamps (not shown) to control flow to and from multiple in-processcontainers 322 a and 322 b. Thus, for example, a clamp on line 370 awould be open, while a clamp on line 370 b would be closed so that cellsexiting separator 301 are directed to (first) in-process container 322a.

For additional washing, cells resuspended in the fresh replacement fluidfrom container 322 a are introduced into separator 301 where the cellsare separated from the supernatant, as previously described. The controlsystem of device 400 closes the clamp (not shown in FIG. 24) on tubingsegment 370 a and opens the clamp (not shown in FIG. 24) on tubingsegment 370 b to allow cells to flow into fresh (second) in-processcontainer 322 b. After the final wash, clamps (not shown) on segments370 a, 370 b, etc., are closed and clamp 372 (as shown, for example, inFIG. 23) is opened to allow collection of the final product in container350.

FIG. 24 shows the front panel 401 of separation device 400; i.e., thehardware, which includes peristaltic pumps 402, 404 and 406. Asdescribed above, pump segments 362, 364 and 368 from the disposable setare selectively associated with peristaltic pumps 402, 404, and 406. Theperistaltic pumps articulate with the fluid set of FIG. 23 at the pumpsegments 362, 364 and 368 and advance the cell suspension within thedisposable set, as will be understood by those of skill in the art. Thecontrol and operation device 400 also includes clamps 410, 412, 414.Clamps 410, 412, 414, and 416 are used to control the flow of the cellsuspension through different segments of the disposable set, asdescribed above.

Device 400 also includes several sensors to measure various conditions.The output of the sensors is utilized by device 400 to operate the washcycle. One or more pressure transducer sensor(s) 426 may be provided ondevice 400 and may be associated with disposable set 300 at certainpoints to monitor the pressure during a procedure. Pressure transducer426 may be integrated into an in-line pressure monitoring site (at, forexample, tubing segment 336), to monitor pressure inside separator 301.Air detector 438 sensor may also be associated with the disposable set300, as necessary. Air detector 438 is optional and may be provided todetect the location of fluid/air interfaces.

Device 400 includes weight scales 440, 442, 444, and 446 from which thefinal bag, in-process bag, cell suspension bag, and any additional bag,respectively, may depend and be weighed. The weights of the bags aremonitored by weight sensors and recorded during a washing procedure.From measurements of the weight sensors, the device determines whethereach bag is empty, partially full, or full and controls the componentsof the control and operation device 200, such as the peristaltic pumpsand clamps 410, 412, 414, 416, 418, 420, 422, and 424.

Device 400 includes at least one drive unit or “spinner” 448, whichcauses the indirect driving of the spinning membrane separator 301.Spinner 448 may consist of a drive motor connected and operated bydevice 400, coupled to turn an annular magnetic drive member includingat least a pair of permanent magnets. As the annular drive member isrotated, magnetic attraction between corresponding magnets within thehousing of the spinning membrane separator cause the spinner within thehousing of the spinning membrane separator to rotate.

FIGS. 26-28 diagrammatically set forth the method of cell washing asdisclosed herein. The steps described below are performed by thesoftware driven microprocessing unit of device 400 with certain stepsperformed by the operator, as noted. Turning first to FIG. 26, thedevice is switched on at step 500. The device conducts self-calibrationchecks 502, including the checking of the peristaltic pumps, clamps, andsensors. Device 400 then prompts the user to enter selected proceduralparameters (step 504), such as the washing procedure to be performed,the amount of cell suspension to be washed, the number of washings totake place, etc. The operator may then select and enter the proceduralparameters for the wash procedure (step 506).

The device (through the controller) confirms the parameter entry 506 andthen prompts the operator to load (step 510) the disposable set. Theoperator then loads the disposable set (step 512) onto the panel ofdevice 400. After installation of the disposable set, the deviceconfirms installation as shown in (step 514).

After the disposable set is mounted, the device automatically checks todetermine whether the disposable set is properly installed (step 516).After the device determines that the disposable set is properlyinstalled, the controller prompts the operator to connect the cellsuspension and wash medium (step 518). The operator then connects thewash medium (such as, but not limited to saline) (step 520) to thedisposable set via a spike connector, as previously described. Theoperator then connects the cell suspension within a product bag (step522) to the disposable set via a spike connector.

As shown in FIG. 27, after the cell suspension and wash medium areconnected to the disposable set, the operator confirms that thesolutions are connected (step 524). The device prompts the operator totake a cell suspension sample (step 526). The operator or the devicethen opens sample pouch clamp 528 to introduce fluid into the samplepouch (step 546). Once the sample pouch is filled, it is then sealed andremoved (542) from the disposable set. The operator confirms (step 544)that a sample has been taken. Following the removal of the sample pouch,the disposable set is primed (step 546) for the wash process.

The controller of separation device then commences the wash process. Thecell suspension to be washed is transferred from its container (e.g.,302 of FIG. 23) through the disposable set to the spinning membraneseparator 301. Likewise, the wash medium is transferred from its source,through the disposable set to the spinning membrane separator 301. In apreferred embodiment, the original cells of the cell suspension areconcentrated and/or collected in either an in-process bag (for furtherprocessing) or collected in a final product bag which is subsequentlyremoved from the disposable set. If (further) washing or diluting of thecell suspension is necessary, the cell suspension in the in-process bagmay be washed (a second time) with the same or different wash mediumfollowing the process outlined above. Prior to the conclusion of eachwash cycle, the cell suspension volume or weight is measured andrecorded (step 550). When the concentration of the cells to wash mediumreaches an acceptable level the final product bag is filled.

As shown in FIG. 28, once the desired volume of the final product iscollected, the control and operation device prompts the operator tosample and seal the final product bag (step 552). A sample pouch isattached to the final product bag. The operator then seals and removesfrom the disposable set the washed cell suspension in the final productbag (step 552). The final product bag is then agitated (step 556). Theoperator opens the sample pouch by removing a clamp (step 558). Thesample pouch is allowed to fill (step 560). Once the sample bag isfilled, the clamp is closed and the sample pouch is sealed and removed(step 562). The operator then seals the disposable set lines (step 564)and confirms that the product bag has been sealed and removed, a samplepouch has been filled and removed, and that the disposable set lineshave been sealed (step 566). The control and operation device thenprompts the operator to remove the disposable set, as shown in step 568.The operator then removes and discards the disposable set, as shown instep 570.

Thus, an improved spinning membrane separator and methods and systemsfor using such a spinning membrane are disclosed. The descriptionprovided above is intended for illustrative purposes only, and is notintended to limit the scope of the disclosure to any specific method,system, or apparatus or device described herein.

What is claimed:
 1. A method for collecting leukoreduced red blood cellsemploying a spinning membrane separator including a membrane configuredto spin about a generally vertically-oriented axis within a housing, thehousing including an upper end region and a lower end region in anoperating position and the separator including a red blood cell outletin the upper end region of the housing and a whole blood inlet in thelower end region of the housing, the method comprising: flowing additivesolution from a first container into the whole blood inlet of thehousing to prime the separator; flowing whole blood into the whole bloodinlet of the housing; separating red blood cells from the whole blood;flowing separated red blood cells out of the red blood cell outlet ofthe housing through a red blood cell flow path; combining the separatedred blood cells with additive solution from the first container in thered blood cell flow path; passing the separated red blood cells andadditive solution combination directly from the red blood cell flow paththrough a leukoreduction filter; and collecting the filtered red bloodcells and additive solution in a second container.
 2. The method ofclaim 1 wherein the additive solution comprises a low-viscositynon-biological fluid.
 3. The method of claim 1 wherein the additivesolution comprises a preservative solution.
 4. The method of claim 1wherein flowing additive solution into the whole blood inlet comprisespumping additive solution into the inlet.
 5. The method of claim 1wherein combining red blood cells with additive solution comprisespumping additive solution into the red blood cell flow path.
 6. Themethod of claim 1 wherein the separated red blood cells and additivesolution combination is pumped through the leukoreduction filter.